ARM: tegra: Enable UDC on AC100

Override the compatible string of the first USB controller to enable
device mode.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Marc Dietrich <marvin24@gmx.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-paz00.dts

@@ -452,7 +452,9 @@ pmc@7000e400 {
 	};
 
 	usb@c5000000 {
+		compatible = "nvidia,tegra20-udc";
 		status = "okay";
+		dr_mode = "peripheral";
 	};
 
 	usb-phy@c5000000 {