HID: usbhid: cancel timer for retry synchronously

This makes sure IO is never restarted while a reset is going on

In particular there seems to be no protection from hid_retry_timeout() calling
hid_start_in() which would start IO after hid_pre_reset() has already called
hid_cease_io() because that uses del_timer(), not del_timer_sync()
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/usbhid/hid-core.c

@@ -1270,7 +1270,7 @@ static void hid_cancel_delayed_stuff(struct usbhid_device *usbhid)
 
 static void hid_cease_io(struct usbhid_device *usbhid)
 {
-	del_timer(&usbhid->io_retry);
+	del_timer_sync(&usbhid->io_retry);
 	usb_kill_urb(usbhid->urbin);
 	usb_kill_urb(usbhid->urbctrl);
 	usb_kill_urb(usbhid->urbout);