[media] au0828: fix case where STREAMOFF being called on stopped stream causes BUG()

We weren't checking whether the resource was in use before calling
res_free(), so applications which called STREAMOFF on a v4l2 device that
wasn't already streaming would cause a BUG() to be hit (MythTV).
Reported-by: Larry Finger <larry.finger@lwfinger.net>
Reported-by: Jay Harbeston <jharbestonus@gmail.com>
Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/au0828/au0828-video.c

@@ -1702,15 +1702,19 @@ static int vidioc_streamoff(struct file *file, void *priv,
 			(AUVI_INPUT(i).audio_setup)(dev, 0);
 		}
 
+		if (res_check(fh, AU0828_RESOURCE_VIDEO)) {
 			videobuf_streamoff(&fh->vb_vidq);
 			res_free(fh, AU0828_RESOURCE_VIDEO);
+		}
 	} else if (fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
 		dev->vbi_timeout_running = 0;
 		del_timer_sync(&dev->vbi_timeout);
 
+		if (res_check(fh, AU0828_RESOURCE_VBI)) {
 			videobuf_streamoff(&fh->vb_vbiq);
 			res_free(fh, AU0828_RESOURCE_VBI);
 		}
+	}
 
 	return 0;
 }