nanopik2-s905: bump u-boot to v2026.04, move eMMC patch

Advance the NanoPi K2 (Amlogic S905) bootloader from v2024.01 to the latest
stable u-boot v2026.04. Move the board patch folder to the new version and
rebase the eMMC-enable patch onto the relocated device tree: in v2026.04 the
DTS moved from arch/arm/dts/ to the synced dts/upstream/ tree. The eMMC node
content is unchanged; verified the patch applies (patch --dry-run / git apply
--check) and nanopi-k2_defconfig still exists upstream.

This also fixes the random MAC address bug: the older u-boot generated a new
random ethernet MAC on every boot, so the board appeared as a different device
each time. The newer u-boot derives a stable MAC, giving a consistent address
across reboots.

Tested on hardware (NanoPi K2): boots from eMMC and keeps a stable MAC across
reboots.

Signed-off-by: Igor Pecovnik <igor@armbian.com>

Author: igorpecovnik

config/boards/nanopik2-s905.conf

@@ -11,5 +11,5 @@ FULL_DESKTOP="yes"
 ASOUND_STATE="asound.state.mesongx"
 BOOT_LOGO="desktop"
 
-BOOTBRANCH_BOARD="tag:v2024.01"
-BOOTPATCHDIR="v2024.01"
+BOOTBRANCH_BOARD="tag:v2026.04"
+BOOTPATCHDIR="v2026.04"

patch/u-boot/v2024.01/board_nanopik2-s905/add-emmc-support-for-nanopi-k2.patch

@@ -0,0 +1,30 @@
+From: Armbian
+Subject: nanopi-k2: enable eMMC (sd_emmc_c) in u-boot device tree
+
+Upstream leaves the eMMC node disabled and tags it with 1.8V DDR/HS200
+modes the NanoPi K2 can't drive in u-boot. Enable the controller and drop
+the 1.8V mode flags so u-boot can read/write the on-board eMMC.
+
+In u-boot v2026.04 the device tree moved from arch/arm/dts/ to the synced
+dts/upstream/ tree, so this targets the new path.
+
+--- a/dts/upstream/src/arm64/amlogic/meson-gxbb-nanopi-k2.dts
++++ b/dts/upstream/src/arm64/amlogic/meson-gxbb-nanopi-k2.dts
+@@ -359,7 +359,7 @@
+
+ /* eMMC */
+ &sd_emmc_c {
+-	status = "disabled";
++	status = "okay";
+ 	pinctrl-0 = <&emmc_pins>, <&emmc_ds_pins>;
+ 	pinctrl-1 = <&emmc_clk_gate_pins>;
+ 	pinctrl-names = "default", "clk-gate";
+@@ -369,8 +369,6 @@
+ 	non-removable;
+ 	disable-wp;
+ 	cap-mmc-highspeed;
+-	mmc-ddr-1_8v;
+-	mmc-hs200-1_8v;
+
+ 	mmc-pwrseq = <&emmc_pwrseq>;
+ 	vmmc-supply = <&vcc3v3>;