ARM: tegra: colibri_t20: iris: add dr_mode property

Add dr_mode property to the USB controller.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-colibri-iris.dts

@@ -145,6 +145,7 @@ i2c_ddc: i2c@7000c400 {
 	/* EHCI instance 0: USB1_DP/N -> USBC_P/N */
 	usb@c5000000 {
 		status = "okay";
+		dr_mode = "otg";
 	};
 
 	usb-phy@c5000000 {