dt-bindings: rcar-gen3-phy-usb2: add no-otg-pins property

This patch adds a new optional property "renesas,no-otg-pins" which
a board does not provide proper otg pins.
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

@@ -34,6 +34,8 @@ channel as USB OTG:
 - interrupts: interrupt specifier for the PHY.
 - vbus-supply: Phandle to a regulator that provides power to the VBUS. This
 	       regulator will be managed during the PHY power on/off sequence.
+- renesas,no-otg-pins: boolean, specify when a board does not provide proper
+		       otg pins.
 
 Example (R-Car H3):