odroidn2: bump u-boot to v2026.07 (#10630)

* odroidn2: move u-boot board patches v2026.04 -> v2026.07

Pure rename, no content changes; prepares the bump of odroidn2 to
u-boot tag:v2026.07. The v2026.04 patch pool stays for other boards.

* odroidn2: bump u-boot to tag:v2026.07

Move ODROID-N2/N2+ from v2026.04 to the v2026.07 release. Board
patches (meson_gx_mmc f_max cap to 24 MHz, USB/NVMe/SCSI-first boot
order) apply cleanly to v2026.07; the f_max cap is still required
since upstream keeps 40 MHz. The shared v2026.07 pool already carries
the btrfs zstd decompression fix and cmd-fileenv.

config/boards/odroidn2.conf

@@ -17,8 +17,8 @@ enable_extension "uboot-btrfs"
 enable_extension "watchdog"
 
 # Newer u-boot for the N2/N2+
-BOOTBRANCH_BOARD="tag:v2026.04"
-BOOTPATCHDIR="v2026.04"
+BOOTBRANCH_BOARD="tag:v2026.07"
+BOOTPATCHDIR="v2026.07"
 
 # Enable writing u-boot to SPI on the N2(+) for current and edge
 # @TODO: replace this with an overlay, after meson64 overlay revamp