dt-bindings: watchdog: renesas,wdt: Document RZ/V2H(P) SoC

Add support for the Watchdog Timer (WDT) hardware found in the Renesas
RZ/V2H(P) SoC to the `renesas,wdt` device tree bindings.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20240829193831.80768-2-prabhakar.mahadev-lad.rj@bp.renesas.com


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