Revert "net: mpls: prevent speculative execution"

CVE-2017-5753 (revert embargoed)
CVE-2017-5715 (revert embargoed)

This reverts commit 021a73b4.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/mpls/af_mpls.c

@@ -43,8 +43,6 @@ static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
 	if (index < net->mpls.platform_labels) {
 		struct mpls_route __rcu **platform_label =
 			rcu_dereference(net->mpls.platform_label);
-
-		gmb();
 		rt = rcu_dereference(platform_label[index]);
 	}
 	return rt;