x25: Fix sleep from timer on socket destroy.

If socket destuction gets delayed to a timer, we try to
lock_sock() from that timer which won't work.

Use bh_lock_sock() in that case.

Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Ingo Molnar <mingo@elte.hu>

net/x25/x25_timer.c

@@ -113,7 +113,7 @@ static void x25_heartbeat_expiry(unsigned long param)
 			    (sk->sk_state == TCP_LISTEN &&
 			     sock_flag(sk, SOCK_DEAD))) {
 				bh_unlock_sock(sk);
-				x25_destroy_socket(sk);
+				x25_destroy_socket_from_timer(sk);
 				return;
 			}
 			break;