USB: chipidea: add vbus detect for udc

Using vbus valid interrupt to detect vbus.

Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Richard Zhao <richard.zhao@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/ci.h

@@ -139,6 +139,7 @@ struct ci13xxx {
 	enum ci_role			role;
 	bool				is_otg;
 	struct work_struct		work;
+	struct work_struct		vbus_work;
 	struct workqueue_struct		*wq;
 
 	struct dma_pool			*qh_pool;