dt-bindings: gpio: renesas,rcar-gpio: R-Car V3U is R-Car Gen4

Despite the name, R-Car V3U is the first member of the R-Car Gen4
family.  Hence move its compatible value to the R-Car Gen4 section.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

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

@@ -48,11 +48,9 @@ properties:
               - renesas,gpio-r8a77995     # R-Car D3
           - const: renesas,rcar-gen3-gpio # R-Car Gen3 or RZ/G2
 
-      - items:
-          - const: renesas,gpio-r8a779a0  # R-Car V3U
-
       - items:
           - enum:
+              - renesas,gpio-r8a779a0     # R-Car V3U
               - renesas,gpio-r8a779f0     # R-Car S4-8
           - const: renesas,rcar-gen4-gpio # R-Car Gen4