V4L/DVB (5988): Fix OOP on videobuf-dvb when hibernating

Since videobuf_waiton is called with intr=1, it can return -EINTR and therefore
err may be non-zero. This happens when the system goes into the standby state.

Without the BUG() occurring, there's no problem with standby mode while DVB
is being used.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/video-buf-dvb.c

@@ -56,7 +56,6 @@ static int videobuf_dvb_thread(void *data)
 				 struct videobuf_buffer, stream);
 		list_del(&buf->stream);
 		err = videobuf_waiton(buf,0,1);
-		BUG_ON(0 != err);
 
 		/* no more feeds left or stop_feed() asked us to quit */
 		if (0 == dvb->nfeeds)