dt-bindings: watchdog: realtek,otto-wdt: add RTL9310

Add the realtek,rtl9310-wdt compatible to the Realtek Otto watchdog
binding.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/84d873d7dd375cd2392f89fa6bd9e0fe5dda4e1c.1656356377.git.sander@svanheule.net


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