isdn: gigaset: add missing unlock

commit 7e27a0ae upstream.

We should unlock here.  This is the only place where we return from the
function with the lock held.  The caller isn't expecting it.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/isdn/gigaset/capi.c

@@ -1044,6 +1044,7 @@ static inline void remove_appl_from_channel(struct bc_state *bcs,
 	do {
 		if (bcap->bcnext == ap) {
 			bcap->bcnext = bcap->bcnext->bcnext;
+			spin_unlock_irqrestore(&bcs->aplock, flags);
 			return;
 		}
 		bcap = bcap->bcnext;