usb: renesas_usbhs: add device tree support for r8a779[23]

Simply document new compatibility string.
As a previous patch adds a generic R-Car Gen2 compatibility string
there appears to be no need for a driver updates.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/usb/renesas_usbhs.txt

@@ -5,6 +5,8 @@ Required properties:
 
 	- "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
+	- "renesas,usbhs-r8a7793" for r8a7793 (R-Car M2-N) compatible device
 	- "renesas,usbhs-r8a7794" for r8a7794 (R-Car E2) compatible device
 	- "renesas,usbhs-r8a7795" for r8a7795 (R-Car H3) compatible device
 	- "renesas,rcar-gen2-usbhs" for R-Car Gen2 compatible device