samples: matter: Allow building nrf54lm20 with wifi ext flash

Allow building nRF54LM20 with nRF70 patch stored on external flash
support. Thanks to that we can save some memory in the internal
memory.

Signed-off-by: Arkadiusz Balys <arkadiusz.balys@nordicsemi.no>

Author: ArekBalysNordic

dts/samples/matter/nrf54lm20_cpuapp_partitions.dtsi

@@ -56,5 +56,20 @@
 			label = "image-1";
 			reg = <0x00000000 DT_SIZE_K(1932)>;
 		};
+
+		slot2_partition: partition@1e3000 {
+			label = "image-2";
+			reg = <0x001e3000 DT_SIZE_K(132)>;
+		};
+
+		nrf70_wifi_fw_partition: nrf70_fw_partition: partition@1e3200 {
+			label = "nrf70-wifi-fw";
+			reg = <0x001e3200 DT_SIZE_K(128)>;
+		};
+
+		slot3_partition: partition@203000 {
+			label = "image-3";
+			reg = <0x00203000 DT_SIZE_K(132)>;
+		};
 	};
 };

samples/matter/template/sample.yaml

@@ -112,6 +112,20 @@ tests:
     platform_allow:
       - nrf54lm20dk/nrf54lm20b/cpuapp
       - nrf54lm20dk/nrf54lm20a/cpuapp
+  sample.matter.template.nrf7002eb2.smp_dfu.ext_patch:
+    sysbuild: true
+    build_only: true
+    extra_args:
+      - CONFIG_CHIP_DFU_OVER_BT_SMP=y
+      - template_SHIELD=nrf7002eb2
+      - SB_CONFIG_WIFI_NRF70=y
+      - SB_CONFIG_WIFI_PATCHES_EXT_FLASH_STORE=y
+    integration_platforms:
+      - nrf54lm20dk/nrf54lm20b/cpuapp
+      - nrf54lm20dk/nrf54lm20a/cpuapp
+    platform_allow:
+      - nrf54lm20dk/nrf54lm20b/cpuapp
+      - nrf54lm20dk/nrf54lm20a/cpuapp
   sample.matter.template.release.internal:
     sysbuild: true
     build_only: true