media: media-request: fix epoll() by calling poll_wait first

The epoll function expects that whenever the poll file op is
called, the poll_wait function is also called. That didn't
always happen in media_request_poll(). Fix this, otherwise
epoll() would timeout when it shouldn't.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/media-request.c

@@ -100,6 +100,7 @@ static __poll_t media_request_poll(struct file *filp,
 	if (!(poll_requested_events(wait) & EPOLLPRI))
 		return 0;
 
+	poll_wait(filp, &req->poll_wait, wait);
 	spin_lock_irqsave(&req->lock, flags);
 	if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
 		ret = EPOLLPRI;
@@ -110,8 +111,6 @@ static __poll_t media_request_poll(struct file *filp,
 		goto unlock;
 	}
 
-	poll_wait(filp, &req->poll_wait, wait);
-
 unlock:
 	spin_unlock_irqrestore(&req->lock, flags);
 	return ret;