dt-bindings: net: renesas,etheravb: Add r8a779g0 support

Document support for the Renesas Ethernet AVB (EtherAVB-IF) block in the
Renesas R-Car V4H (R8A779G0) SoC.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Wolfram Sang <[e-mail]>
Reviewed-by: Sergey Shtylyov <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/devicetree/bindings/net/renesas,etheravb.yaml

···
       - items:
           - enum:
               - renesas,etheravb-r8a779a0     # R-Car V3U
+              - renesas,etheravb-r8a779g0     # R-Car V4H
           - const: renesas,etheravb-rcar-gen4 # R-Car Gen4
 
       - items:
···
               - renesas,etheravb-r8a77965
               - renesas,etheravb-r8a77970
               - renesas,etheravb-r8a77980
-              - renesas,etheravb-r8a779a0
+              - renesas,etheravb-rcar-gen4
     then:
       required:
         - tx-internal-delay-ps