mpls: fix mpls_net_init memory leak

Fix a memory leak in the mpls netns init function in case of failure. If
register_net_sysctl fails then we need to free the ctl_table.

Fixes: 7720c01f3f59 ("mpls: Add a sysctl to control the size of the mpls label table")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mpls/af_mpls.c

@@ -1177,8 +1177,10 @@ static int mpls_net_init(struct net *net)
 
 	table[0].data = net;
 	net->mpls.ctl = register_net_sysctl(net, "net/mpls", table);
-	if (net->mpls.ctl == NULL)
+	if (net->mpls.ctl == NULL) {
+		kfree(table);
 		return -ENOMEM;
+	}
 
 	return 0;
 }