Documentation: dt-bindings: update the meson-usb2-phy example

Update the example so the node name uses a dash (instead of an
underscore) as per convention.
Additionally it updates the example register offset to a real example
(the old value was taken from a draft where there was an additional PHY
bus).
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMartin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/meson-usb2-phy.txt

@@ -16,10 +16,10 @@ Optional properties:
 
 Example:
 
-usb0_phy: usb_phy@0 {
+usb0_phy: usb-phy@c0000000 {
 	compatible = "amlogic,meson-gxbb-usb2-phy";
 	#phy-cells = <0>;
-	reg = <0x0 0x0 0x0 0x20>;
+	reg = <0x0 0xc0000000 0x0 0x20>;
 	resets = <&reset RESET_USB_OTG>;
 	clocks = <&clkc CLKID_USB>, <&clkc CLKID_USB0>;
 	clock-names = "usb_general", "usb";