dt-bindings: watchdog: img,pdc-wdt: Convert to dtschema

Convert txt bindings of ImgTec's PDC watchdog timer to dtschema to allow
for validation.

Signed-off-by: Shresth Prasad <shrestprasad7@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240527195811.7897-2-shresthprasad7@gmail.com


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