staging: dwc2: update DT binding to add generic clock/phy properties

dwc2/s3c-hsotg require a single clock to be specified and optionally
a generic phy. On the s3c-hsotg driver old style USB phy support is
present as a fallback so the generic phy properties are optional.
Signed-off-by: Matt Porter <mporter@linaro.org>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/staging/dwc2.txt

@@ -5,6 +5,14 @@ Required properties:
 - compatible : "snps,dwc2"
 - reg : Should contain 1 register range (address and length)
 - interrupts : Should contain 1 interrupt
+- clocks: clock provider specifier
+- clock-names: shall be "otg"
+Refer to clk/clock-bindings.txt for generic clock consumer properties
+
+Optional properties:
+- phys: phy provider specifier
+- phy-names: shall be "device"
+Refer to phy/phy-bindings.txt for generic phy consumer properties
 
 Example:
 
@@ -12,4 +20,8 @@ Example:
                 compatible = "ralink,rt3050-usb, snps,dwc2";
                 reg = <0x101c0000 40000>;
                 interrupts = <18>;
+		clocks = <&usb_otg_ahb_clk>;
+		clock-names = "otg";
+		phys = <&usbphy>;
+		phy-names = "usb2-phy";
         };