usb: chipidea: udc: Consolidate the call of disconnect

The udc-core will call gadget's driver->disconnect, so we should avoid
calling gadget's disconnect again at ci_udc_stop in case the gadget's
unbind free some structs which is still used at gadget's disconnect.
Tested-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/udc.c

@@ -686,9 +686,6 @@ static int _gadget_stop_activity(struct usb_gadget *gadget)
 	usb_ep_fifo_flush(&ci->ep0out->ep);
 	usb_ep_fifo_flush(&ci->ep0in->ep);
 
-	if (ci->driver)
-		ci->driver->disconnect(gadget);
-
 	/* make sure to disable all endpoints */
 	gadget_for_each_ep(ep, gadget) {
 		usb_ep_disable(ep);
@@ -717,6 +714,11 @@ __acquires(ci->lock)
 {
 	int retval;
 
+	if (ci->gadget.speed != USB_SPEED_UNKNOWN) {
+		if (ci->driver)
+			ci->driver->disconnect(&ci->gadget);
+	}
+
 	spin_unlock(&ci->lock);
 	retval = _gadget_stop_activity(&ci->gadget);
 	if (retval)
@@ -1461,6 +1463,8 @@ static int ci_udc_vbus_session(struct usb_gadget *_gadget, int is_active)
 			hw_device_state(ci, ci->ep0out->qh.dma);
 			dev_dbg(ci->dev, "Connected to host\n");
 		} else {
+			if (ci->driver)
+				ci->driver->disconnect(&ci->gadget);
 			hw_device_state(ci, 0);
 			if (ci->platdata->notify_event)
 				ci->platdata->notify_event(ci,