ARM: tegra: add DT nodes for Tegra USB PHY

Add DT nodes for Tegra USB PHY along with related documentation.
Also added a phandle property to controller DT node, for referring
to connected PHY instance.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt b/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
index 6ea765a..34c9528 100644
--- a/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
+++ b/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
@@ -11,6 +11,7 @@
  - phy_type : Should be one of "ulpi" or "utmi".
  - nvidia,vbus-gpio : If present, specifies a gpio that needs to be
    activated for the bus to be powered.
+ - nvidia,phy : phandle of the PHY instance, the controller is connected to.
 
 Required properties for phy_type == ulpi:
   - nvidia,phy-reset-gpio : The GPIO used to reset the PHY.