dt-bindings: usb: Add usb-phy property to the jz4740-musb node

Add a required 'usb-phy' property, to obtain a phandle to the USB PHY
from devicetree.

Signed-off-by: Paul Cercueil <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Bin Liu <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/ingenic,jz4740-musb.txt

···
 - interrupt-names: must be "mc"
 - clocks: phandle to the "udc" clock
 - clock-names: must be "udc"
+- phys: phandle to the USB PHY
 
 Example:
+
+usb_phy: usb-phy@0 {
+	compatible = "usb-nop-xceiv";
+	#phy-cells = <0>;
+};
 
 udc: usb@13040000 {
 	compatible = "ingenic,jz4740-musb";
···
 
 	clocks = <&cgu JZ4740_CLK_UDC>;
 	clock-names = "udc";
+
+	phys = <&usb_phy>;
 };