[NETFILTER]: nfnetlink_log: fix use after free

Paranoia: instance_put() might have freed the inst pointer when we
spin_unlock_bh().
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

net/netfilter/nfnetlink_log.c

@@ -380,8 +380,8 @@ static void nfulnl_timer(unsigned long data)
 	if (timer_pending(&inst->timer))	/* is it always true or false here? */
 		del_timer(&inst->timer);
 	__nfulnl_send(inst);
-	instance_put(inst);
 	spin_unlock_bh(&inst->lock);
+	instance_put(inst);
 }
 
 static inline int