ARM: dts: omap5: Fix dual-role mode on Super-Speed port

OMAP5's Super-Speed USB port has a software mailbox register
that needs to be fed with VBUS and ID events from an external
VBUS/ID comparator.

Without this, Host role will not work correctly.

Fixes: 656c1a65 ("ARM: dts: omap5: enable OTG role for DWC3 controller")
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/omap5-board-common.dtsi

@@ -701,6 +701,7 @@ &usb3 {
 };
 
 &dwc3 {
+	extcon = <&extcon_usb3>;
 	dr_mode = "otg";
 };