usb: musb: gadget: use udc-core's reset notifier

Replace usb_gadget_driver's disconnect with udc-core's reset notifier at
bus reset handler.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_gadget.c

@@ -2083,9 +2083,12 @@ __acquires(musb->lock)
 				: NULL
 			);
 
-	/* report disconnect, if we didn't already (flushing EP state) */
-	if (musb->g.speed != USB_SPEED_UNKNOWN)
-		musb_g_disconnect(musb);
+	/* report reset, if we didn't already (flushing EP state) */
+	if (musb->gadget_driver && musb->g.speed != USB_SPEED_UNKNOWN) {
+		spin_unlock(&musb->lock);
+		usb_gadget_udc_reset(&musb->g, musb->gadget_driver);
+		spin_lock(&musb->lock);
+	}
 
 	/* clear HR */
 	else if (devctl & MUSB_DEVCTL_HR)