Wire the RTL8721F (amebagreen2) into the shared Ameba watchdog driver
(arch/arm/src/common/ameba/ameba_wdg.c), registered as /dev/watchdog0.
Only the per-chip base address and IRQ differ, so this adds a small
ameba_wdg_chip.h (WDG2 non-secure system watchdog at 0x4080AD80,
CPU0_NS_WDG IRQ 69, verified against the SoC hal_platform.h and
ameba_vector_table.h) plus the Make.defs/CMakeLists build hooks, the
board bring-up registration, and a wdg defconfig. The shared driver is
unchanged.
Assisted-by: Claude <noreply@anthropic.com>
Signed-off-by: dechao_gong <dechao_gong@realsil.com.cn>