dt-bindings: usb: renesas_usbhs: Add r8a774a1 support

Document RZ/G2M (R8A774A1) SoC bindings.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/renesas_usbhs.txt

@@ -5,6 +5,7 @@ Required properties:
 
 	- "renesas,usbhs-r8a7743" for r8a7743 (RZ/G1M) compatible device
 	- "renesas,usbhs-r8a7745" for r8a7745 (RZ/G1E) compatible device
+	- "renesas,usbhs-r8a774a1" for r8a774a1 (RZ/G2M) compatible device
 	- "renesas,usbhs-r8a7790" for r8a7790 (R-Car H2) compatible device
 	- "renesas,usbhs-r8a7791" for r8a7791 (R-Car M2-W) compatible device
 	- "renesas,usbhs-r8a7792" for r8a7792 (R-Car V2H) compatible device
@@ -16,7 +17,7 @@ Required properties:
 	- "renesas,usbhs-r8a77995" for r8a77995 (R-Car D3) compatible device
 	- "renesas,usbhs-r7s72100" for r7s72100 (RZ/A1) compatible device
 	- "renesas,rcar-gen2-usbhs" for R-Car Gen2 or RZ/G1 compatible devices
-	- "renesas,rcar-gen3-usbhs" for R-Car Gen3 compatible device
+	- "renesas,rcar-gen3-usbhs" for R-Car Gen3 or RZ/G2 compatible devices
 	- "renesas,rza1-usbhs" for RZ/A1 compatible device
 
 	When compatible with the generic version, nodes must list the