dt-bindings: watchdog: Add watchdog for StarFive JH7100 and JH7110

Add bindings to describe the watchdog for the StarFive JH7100/JH7110 SoC.
And Use JH7100 as first StarFive SoC with watchdog.

Signed-off-by: Xingyu Wu <xingyu.wu@starfivetech.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230314132437.121534-2-xingyu.wu@starfivetech.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>