Videopix Frame Grabber: Fix unreleased lock in vfc_debug()

Videopix Frame Grabber: vfc_debug() doesn't release the device lock
when copy_from_user() fails

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/sbus/char/vfc_dev.c

@@ -248,6 +248,7 @@ static int vfc_debug(struct vfc_dev *dev, int cmd, void __user *argp)
 					buffer,inout.len);
 
 		if (copy_to_user(argp,&inout,sizeof(inout))) {
+			vfc_unlock_device(dev);
 			kfree(buffer);
 			return -EFAULT;
 		}