dt-bindings: watchdog: realtek,otto-wdt: simplify requiring interrupt-names

Required properties should be listed in "required:" block. Since
interrupts are already there, the dependency of interrupt-names on the
interrupts can be simplified.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Sander Vanheule <sander@svanheule.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230415095112.51257-6-krzysztof.kozlowski@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>