dt-bindings: rcar-gen3-phy-usb2: Add bindings for r8a77990

This patch adds suuport for r8a77990 (R-Car E3).
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt

@@ -10,6 +10,8 @@ Required properties:
 	      SoC.
 	      "renesas,usb2-phy-r8a77965" if the device is a part of an
 	      R8A77965 SoC.
+	      "renesas,usb2-phy-r8a77990" if the device is a part of an
+	      R8A77990 SoC.
 	      "renesas,usb2-phy-r8a77995" if the device is a part of an
 	      R8A77995 SoC.
 	      "renesas,rcar-gen3-usb2-phy" for a generic R-Car Gen3 compatible device.