ARM: tegra: add USB ULPI PHY reset GPIO to device tree

ULPI PHYs have a reset signal, and different boards use a different GPIO
for this task. Add a property to device tree to represent this.

I'm not sure if adding this property to the EHCI controller node is
entirely correct; perhaps eventually we should have explicit separate
nodes for the various PHYs. However, we don't have that right now, so this
binding seems like a reasonable choice.

Cc: <devicetree-discuss@lists.ozlabs.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/arch/arm/boot/dts/tegra-trimslice.dts b/arch/arm/boot/dts/tegra-trimslice.dts
index 98efd5b..71b73aa 100644
--- a/arch/arm/boot/dts/tegra-trimslice.dts
+++ b/arch/arm/boot/dts/tegra-trimslice.dts
@@ -304,4 +304,8 @@
 		cd-gpios = <&gpio 121 0>;
 		wp-gpios = <&gpio 122 0>;
 	};
+
+	usb@c5004000 {
+		nvidia,phy-reset-gpio = <&gpio 168 0>; /* gpio PV0 */
+	};
 };