V4L/DVB (8022): saa7134: fix race between opening and closing the device

decrementing dev->empress_users should be done as last action of ts_release,
because it sleeps and write access to dev->empress_started is not protected
in any way
(additionally closing thread could mute audio after opening thread unmuted it)
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/saa7134/saa7134-empress.c

@@ -112,7 +112,6 @@ static int ts_release(struct inode *inode, struct file *file)
 
 	videobuf_stop(&dev->empress_tsq);
 	videobuf_mmap_free(&dev->empress_tsq);
-	dev->empress_users--;
 
 	/* stop the encoder */
 	ts_reset_encoder(dev);
@@ -121,6 +120,8 @@ static int ts_release(struct inode *inode, struct file *file)
 	saa_writeb(SAA7134_AUDIO_MUTE_CTRL,
 		saa_readb(SAA7134_AUDIO_MUTE_CTRL) | (1 << 6));
 
+	dev->empress_users--;
+
 	return 0;
 }