samples: bluetooth: fast_pair: locator_tag: migrate nRF53 targets to DTS

Migrated the Fast Pair Locator Tag sample on the nRF53 board targets
away from the deprecated Partition Manager static YAML files to a
DTS-based partition layout, in line with the migration style
established for the remaining board targets. Documentation updates that
go beyond the sample-local README is done in an independent commit.

Affected board targets:

- nrf5340dk/nrf5340/cpuapp
- thingy53/nrf5340/cpuapp

Application core changes (configuration/boards/*_cpuapp.overlay):

- Defined the full flash0 partition layout (boot_partition,
  slot0_partition, bt_fast_pair_partition, storage_partition).
- Defined the mx25r64 partition layout for slot1_partition (956 KB,
  matching the original PM offsets) and slot3_partition.
- Set slot3_partition to DT_SIZE_K(224) so it matches the upstream
  RAM-backed slot2_partition in nrf/modules/mcuboot/flash_sim.overlay
  that MCUboot uses to forward the network core image.
- Used DT_SIZE_K() consistently for partition sizes.
- Removed the per-board common dtsi files; both /ns variants and the
  related dtsi includes are gone with the /ns scope removal.

Sysbuild overlays (sysbuild/{ipc_radio,b0n,mcuboot}/boards/):

- Introduced a single ipc_radio cpunet overlay that defines
  b0n_partition (matches the Matter reference layout), the
  bl_storage / provision_partition node and s0_partition sized at
  DT_SIZE_K(222) so that ih_img_size + ih_hdr_size still fit in the
  224 KB flash_sim slot when MCUboot validates the staged network
  core image.
- The b0n overlay reuses the IPC radio cpunet layout via a relative
  include and only sets zephyr,code-partition to b0n_partition,
  avoiding any duplication of the cpunet partition map.
- The MCUboot overlays continue to include the cpuapp overlay and
  point zephyr,code-partition at boot_partition.
- Disabled CONFIG_MCUBOOT_VERIFY_IMG_ADDRESS, which depends on PM-only
  macros for the network core slot.

Sysbuild configuration (sysbuild/configuration/*/sysbuild.conf):

- Disabled SB_CONFIG_PARTITION_MANAGER for the nRF53 board targets.
- Kept SB_CONFIG_SECURE_BOOT_NETCORE=y and
  SB_CONFIG_NETCORE_APP_UPDATE=y so that the upstream s0-partition
  and flash_sim overlays apply, and aligned the layout with
  SB_CONFIG_MCUBOOT_NRF53_MULTI_IMAGE_UPDATE.

Removed /ns scope (per updated NCSDK-38010 description):

- Deleted nrf5340dk/nrf5340/cpuapp/ns and
  thingy53/nrf5340/cpuapp/ns board configs, overlays, PM static
  YAMLs, sysbuild folders, and signature key files.
- Removed the matching entries from sample.yaml.

Project-wide configuration:

- Moved CONFIG_USE_DT_CODE_PARTITION=y from per-board *.conf files
  to configuration/prj.conf and configuration/prj_release.conf, and
  highlighted it with a leading blank line, mirroring the style of
  nrf/samples/bluetooth/fast_pair/input_device/prj.conf. Now that
  every supported target is on DTS partitioning, the option only
  needs to be set once at the sample level. The b0n image keeps its
  own CONFIG_USE_DT_CODE_PARTITION=y in sysbuild/b0n/prj.conf since
  it is a separate sysbuild image.

README.rst alignment:

- Removed nrf5340dk/nrf5340/cpuapp/ns and thingy53/nrf5340/cpuapp/ns
  from the DFU solution and signature algorithm tables.
- Dropped the /includes/build_and_run_ns.txt include from the
  Building and running section, as no /ns variant is supported now.

Ref: NCSDK-38010

Signed-off-by: Kamil Piszczek <Kamil.Piszczek@nordicsemi.no>

Author: kapi-no

samples/bluetooth/fast_pair/locator_tag/README.rst

@@ -229,9 +229,7 @@ The configuration of the DFU solution varies depending on the board target:
 |              |                                | * ``nrf54ls05dk/nrf54ls05b/cpuapp`` (only ``release`` configuration) |
 +--------------+--------------------------------+----------------------------------------------------------------------+
 | MCUboot      | overwrite only mode            | * ``nrf5340dk/nrf5340/cpuapp``                                       |
-|              |                                | * ``nrf5340dk/nrf5340/cpuapp/ns``                                    |
 |              |                                | * ``thingy53/nrf5340/cpuapp``                                        |
-|              |                                | * ``thingy53/nrf5340/cpuapp/ns``                                     |
 +--------------+--------------------------------+----------------------------------------------------------------------+
 
 Signature algorithm
@@ -250,9 +248,7 @@ The configuration of the signature algorithm and the public key storage solution
 | RSA-2048                       | * ``nrf52dk/nrf52832`` (only ``release`` configuration)              | Bootloader partition      | SW calculation,           |
 |                                | * ``nrf52833dk/nrf52833`` (only ``release`` configuration)           |                           | Signature derived from    |
 |                                | * ``nrf5340dk/nrf5340/cpuapp``                                       |                           | image hash                |
-|                                | * ``nrf5340dk/nrf5340/cpuapp/ns``                                    |                           |                           |
 |                                | * ``thingy53/nrf5340/cpuapp``                                        |                           |                           |
-|                                | * ``thingy53/nrf5340/cpuapp/ns``                                     |                           |                           |
 +--------------------------------+----------------------------------------------------------------------+---------------------------+---------------------------+
 | ECDSA-P256                     | * ``nrf52840dk/nrf52840``                                            | Bootloader partition      | HW-accelerated            |
 |                                |                                                                      |                           | (Cryptocell 310),         |
@@ -679,8 +675,6 @@ Building and running
 
 .. |sample path| replace:: :file:`samples/bluetooth/fast_pair/locator_tag`
 
-.. include:: /includes/build_and_run_ns.txt
-
 .. |sample_or_app| replace:: sample
 .. |ipc_radio_dir| replace:: :file:`sysbuild/ipc_radio`
 

samples/bluetooth/fast_pair/locator_tag/configuration/boards/nrf52833dk_nrf52833.conf

@@ -1,7 +1,59 @@
 /*
- * Copyright (c) 2024 Nordic Semiconductor ASA
+ * Copyright (c) 2024-2026 Nordic Semiconductor ASA
  *
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
-#include "nrf5340dk_nrf5340_cpuapp_common.dtsi"
+&flash0 {
+	/* Redefine the "partitions" DTS node. */
+	/delete-node/ partitions;
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		boot_partition: partition@0 {
+			label = "mcuboot";
+			reg = <0x0 DT_SIZE_K(48)>;
+		};
+
+		slot0_partition: partition@c000 {
+			label = "image-0";
+			reg = <0xc000 DT_SIZE_K(956)>;
+		};
+
+		bt_fast_pair_partition: partition@fb000 {
+			reg = <0xfb000 DT_SIZE_K(4)>;
+		};
+
+		storage_partition: partition@fc000 {
+			label = "storage";
+			reg = <0xfc000 DT_SIZE_K(16)>;
+		};
+	};
+};
+
+&mx25r64 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		slot1_partition: partition@0 {
+			label = "image-1";
+			reg = <0x0 DT_SIZE_K(956)>;
+		};
+
+		/*
+		 * The network core secondary slot must be the same size as
+		 * the corresponding RAM-backed slot2_partition (224 KB). Refer
+		 * to nrf/modules/mcuboot/flash_sim.overlay for the slot2_partition
+		 * definition.
+		 */
+		slot3_partition: partition@ef000 {
+			label = "image-3";
+			reg = <0xef000 DT_SIZE_K(224)>;
+		};
+	};
+};

samples/bluetooth/fast_pair/locator_tag/configuration/boards/nrf52840dk_nrf52840.conf

@@ -31,6 +31,3 @@ CONFIG_PSA_USE_CRACEN_KEY_AGREEMENT_DRIVER=n
 CONFIG_PSA_USE_CRACEN_KEY_DERIVATION_DRIVER=n
 CONFIG_PSA_USE_CRACEN_KEY_MANAGEMENT_DRIVER=n
 CONFIG_CRACEN_LIB_KMU=n
-
-# Enable code partitioning with DTS
-CONFIG_USE_DT_CODE_PARTITION=y