dt-bindings: net: ravb: Add support for r8a774b1 SoC

Document RZ/G2N (R8A774B1) SoC bindings.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/renesas,ravb.txt

@@ -18,6 +18,7 @@ Required properties:
 		R-Car Gen2 and RZ/G1 devices.
 
       - "renesas,etheravb-r8a774a1" for the R8A774A1 SoC.
+      - "renesas,etheravb-r8a774b1" for the R8A774B1 SoC.
       - "renesas,etheravb-r8a774c0" for the R8A774C0 SoC.
       - "renesas,etheravb-r8a7795" for the R8A7795 SoC.
       - "renesas,etheravb-r8a7796" for the R8A7796 SoC.