dt-bindings: serial: renesas: Document RZ/G2M v3.0 (r8a774a3) scif

Document scif bindings for the Renesas RZ/G2M v3.0 (a.k.a r8a774a3) SoC.
Signed-off-by: Oliver Rhodes <oliver.rhodes.aj@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20240725100534.5374-6-oliver.rhodes.aj@renesas.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/renesas,scif.yaml

@@ -46,6 +46,7 @@ properties:
       - items:
           - enum:
               - renesas,scif-r8a774a1     # RZ/G2M
+              - renesas,scif-r8a774a3     # RZ/G2M v3.0
               - renesas,scif-r8a774b1     # RZ/G2N
               - renesas,scif-r8a774c0     # RZ/G2E
               - renesas,scif-r8a774e1     # RZ/G2H