[media] uvcvideo: Fix race of open and suspend in error case

Ming Lei reported:
IMO, there is a minor fault in the error handling path of
uvc_status_start() inside uvc_v4l2_open(), and the 'users' count should
have been decreased before usb_autopm_put_interface(). In theory, a [URB
resubmission] warning can be triggered when the device is opened just
between usb_autopm_put_interface() and atomic_dec(&stream->dev->users).
The fix is trivial.

Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/uvc/uvc_v4l2.c

@@ -501,8 +501,8 @@ static int uvc_v4l2_open(struct file *file)
 	if (atomic_inc_return(&stream->dev->users) == 1) {
 		ret = uvc_status_start(stream->dev);
 		if (ret < 0) {
-			usb_autopm_put_interface(stream->dev->intf);
 			atomic_dec(&stream->dev->users);
+			usb_autopm_put_interface(stream->dev->intf);
 			kfree(handle);
 			return ret;
 		}