dt-bindings: net: renesas,etheravb: Document RZ/G3S support

Document Ethernet RZ/G3S support. Ethernet IP is similar to the one
available on RZ/G2L devices.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -58,6 +58,7 @@ properties:
               - renesas,r9a07g043-gbeth # RZ/G2UL and RZ/Five
               - renesas,r9a07g044-gbeth # RZ/G2{L,LC}
               - renesas,r9a07g054-gbeth # RZ/V2L
+              - renesas,r9a08g045-gbeth # RZ/G3S
           - const: renesas,rzg2l-gbeth  # RZ/{G2L,G2UL,V2L} family
 
   reg: true