colibri-imx6ull: fix usb host mode

This fixes an issue with USB host mode.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@toradex.com>
diff --git a/arch/arm/dts/imx6ull-colibri.dts b/arch/arm/dts/imx6ull-colibri.dts
index 4196cbd..6c847ab 100644
--- a/arch/arm/dts/imx6ull-colibri.dts
+++ b/arch/arm/dts/imx6ull-colibri.dts
@@ -220,7 +220,7 @@
 
 /* Colibri USBC */
 &usbotg1 {
-	dr_mode = "otg";
+	dr_mode = "host";
 	srp-disable;
 	hnp-disable;
 	adp-disable;