V4L/DVB (10261): em28xx: fix kernel panic on audio shutdown

Revert a change made in change 9743 which resulted in a kernel panic in some
cases on shutdown of the audio stream.

First discovered when working on the Pinnacle 880e support, and later
reproduced by a user on the mailing list with the HVR-900 as well.
Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-audio.c

@@ -62,7 +62,7 @@ static int em28xx_isoc_audio_deinit(struct em28xx *dev)
 
 	dprintk("Stopping isoc\n");
 	for (i = 0; i < EM28XX_AUDIO_BUFS; i++) {
-		usb_unlink_urb(dev->adev.urb[i]);
+		usb_kill_urb(dev->adev.urb[i]);
 		usb_free_urb(dev->adev.urb[i]);
 		dev->adev.urb[i] = NULL;