Convert txt bindings of TI's DaVinci/Keystone Watchdog Timer Controller
to dtschema to allow for validation.

While at it,
- Change the order of the compatibles.
- Add "power-domains" to represent that the power domain maybe managed by
  TI-SCI controller if found on the SoC (for example, Keystone based K2G).

w.r.t. to the txt binding to stay in sync with existing DTS.
Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240727050736.4756-3-five231003@gmail.comSigned-off-by: Rob Herring (Arm) <robh@kernel.org>