dt-bindings: gpio: rcar: Add r8a774c0 (RZ/G2E) support

Document Renesas' RZ/G2E (R8A774C0) GPIO blocks compatibility within the
relevant dt-bindings.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt

@@ -8,6 +8,7 @@ Required Properties:
     - "renesas,gpio-r8a7745": for R8A7745 (RZ/G1E) compatible GPIO controller.
     - "renesas,gpio-r8a77470": for R8A77470 (RZ/G1C) compatible GPIO controller.
     - "renesas,gpio-r8a774a1": for R8A774A1 (RZ/G2M) compatible GPIO controller.
+    - "renesas,gpio-r8a774c0": for R8A774C0 (RZ/G2E) compatible GPIO controller.
     - "renesas,gpio-r8a7778": for R8A7778 (R-Car M1) compatible GPIO controller.
     - "renesas,gpio-r8a7779": for R8A7779 (R-Car H1) compatible GPIO controller.
     - "renesas,gpio-r8a7790": for R8A7790 (R-Car H2) compatible GPIO controller.