dt-bindings: watchdog: add support for Amlogic A4 SoCs

Update dt-binding document for watchdog of Amlogic A4 SoCs.

Signed-off-by: Huqiang Qin <huqiang.qin@amlogic.com>
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240709-a4-a5_watchdog-v1-1-2ae852e05ec2@amlogic.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>