[NETFILTER]: nfnetlink_log: fix possible NULL pointer dereference

Eliminate possible NULL pointer dereference in nfulnl_recv_config().

Signed-off-by: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 1b94051..b669db5 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -858,6 +858,9 @@
 			ret = -EINVAL;
 			break;
 		}
+
+		if (!inst)
+			goto out;
 	} else {
 		if (!inst) {
 			UDEBUG("no config command, and no instance for "
@@ -911,6 +914,7 @@
 
 out_put:
 	instance_put(inst);
+out:
 	return ret;
 }