phy: omap-usb2: Add clock names to Documentation binding

Add "wkupclk" and "refclk" information to DT binding information.

Reviewed-by: Felipe Balbi <[e-mail]>
Signed-off-by: Roger Quadros <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

Documentation/devicetree/bindings/phy/ti-phy.txt

···
  - reg : Address and length of the register set for the device.
  - #phy-cells: determine the number of cells that should be given in the
    phandle while referencing this phy.
+ - clocks: a list of phandles and clock-specifier pairs, one for each entry in
+   clock-names.
+ - clock-names: should include:
+   * "wkupclk" - wakeup clock.
+   * "refclk" - reference clock (optional).
 
 Optional properties:
  - ctrl-module : phandle of the control module used by PHY driver to power on
···
 	reg = <0x4a0ad080 0x58>;
 	ctrl-module = <&omap_control_usb>;
 	#phy-cells = <0>;
+	clocks = <&usb_phy_cm_clk32k>, <&usb_otg_ss_refclk960m>;
+	clock-names = "wkupclk", "refclk";
 };
 
 TI PIPE3 PHY