dt-bindings: watchdog: renesas,wdt: Document RZ/G3E support

Document the support for the watchdog IP available on RZ/G3E SoC. The
watchdog IP available on RZ/G3E SoC is identical to the one found on
RZ/V2H SoC.

Reviewed-by: Geert Uytterhoeven <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Tommaso Merciai <[e-mail]>
Signed-off-by: Biju Das <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>

Documentation/devicetree/bindings/watchdog/renesas,wdt.yaml

···
               - renesas,r8a779h0-wdt     # R-Car V4M
           - const: renesas,rcar-gen4-wdt # R-Car Gen4
 
+      - items:
+          - const: renesas,r9a09g047-wdt # RZ/G3E
+          - const: renesas,r9a09g057-wdt # RZ/V2H(P)
+
       - const: renesas,r9a09g057-wdt       # RZ/V2H(P)
 
   reg: