isdn/gigaset: bas_gigaset locking fix

Unlock cs->lock before calling error_hangup() which is marked
"cs->lock must not be held".

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
CC: stable <stable@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed