boards: declare ARCH=arm64 explicitly on five inheriting boards

Five board configs were inheriting their architecture either implicitly
(via BOARDFAMILY → kernel-config selection) or by sourcing another
board's .csc and never overriding it. Declare ARCH explicitly so that
arch-aware tooling (e.g. the build matrix filter that picks which
boards a release/arch target should fan out to) can match them by a
direct field read instead of having to re-evaluate the
BOARDFAMILY-to-arch chain.

Boards touched:

  aml-t95z-plus.tvb         BOARDFAMILY=meson-gxl   → ARCH=arm64
  ayn-odin2mini.csc         (sources ayn-odin2.csc) → ARCH=arm64
  ayn-odin2portal.csc       (sources ayn-odin2.csc) → ARCH=arm64
  ayn-thor.csc              (sources ayn-odin2.csc) → ARCH=arm64
  gateway-dk.conf           BOARDFAMILY=ls1046a     → ARCH=arm64

No build behaviour change for these boards: the resolved ARCH was
already arm64 via inheritance, the declaration just makes it
addressable at config-load time without sourcing the kernel config
chain.

Also clean up a stray apostrophe in aml-t95z-plus.tvb's BOARDFAMILY
comment ("s912's" → "s912s").

Author: igorpecovnik

config/boards/aml-t95z-plus.tvb

@@ -2,7 +2,8 @@
 BOARD_NAME="T95Z Plus"                          #  (a q201 Chinese clone with internal amlogic ethernet 1gbit, complete with a chunk of metal inside to delay thermal throttling)
 BOARD_VENDOR="amlogic"
 BOOT_FDT_FILE="amlogic/meson-gxm-t95z-plus.dtb" # From chewitt's patches
-BOARDFAMILY="meson-gxl"                         # s912's are actually meson-gxm, no harm done.
+BOARDFAMILY="meson-gxl"                         # s912s are actually meson-gxm, no harm done.
+ARCH="arm64"
 BOARD_VENDOR="generic"
 BOOTCONFIG="meson-gxm-t95z-plus_defconfig"      # patched-in
 BOARD_MAINTAINER=""

config/boards/ayn-odin2mini.csc

@@ -1,5 +1,6 @@
 # Qualcomm SM8550 octa core 8GB/12GB/16GB RAM SoC eMMC USB-C WiFi/BT
 source "${SRC}/config/boards/ayn-odin2.csc"
+declare -g ARCH="arm64"
 declare -g BOARD_NAME="Ayn Odin2 Mini"
 declare -g BOARD_VENDOR="ayntec"
 declare -g BOARD_MAINTAINER="Squishy123"

config/boards/ayn-odin2portal.csc

@@ -1,5 +1,6 @@
 # Qualcomm SM8550 octa core 8GB/12GB/16GB RAM SoC eMMC USB-C WiFi/BT
 source "${SRC}/config/boards/ayn-odin2.csc"
+declare -g ARCH="arm64"
 declare -g BOARD_NAME="Ayn Odin2 Portal"
 declare -g BOARD_VENDOR="ayntec"
 declare -g BOARD_MAINTAINER="Squishy123"

config/boards/ayn-thor.csc

@@ -1,5 +1,6 @@
 # Qualcomm SM8550 octa core 8GB/12GB/16GB RAM SoC eMMC USB-C WiFi/BT
 source "${SRC}/config/boards/ayn-odin2.csc"
+declare -g ARCH="arm64"
 declare -g BOARD_NAME="Ayn Thor"
 declare -g BOARD_VENDOR="ayntec"
 declare -g BOARD_MAINTAINER="Squishy123"

config/boards/gateway-dk.conf

@@ -2,6 +2,7 @@
 BOARD_NAME="Mono Gateway Development Kit"
 BOARD_VENDOR="mono"
 BOARDFAMILY="ls1046a"
+ARCH="arm64"
 BOARD_MAINTAINER="tomazzaman"
 BOOTCONFIG="mono_gateway_dk_defconfig"
 KERNEL_TARGET="current"