[NETFILTER]: nf_nat_proto_gre: add missing module reference

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
index b820f99..945e0ae 100644
--- a/net/ipv4/netfilter/nf_nat_proto_gre.c
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c
@@ -138,6 +138,7 @@
 static struct nf_nat_protocol gre __read_mostly = {
 	.name			= "GRE",
 	.protonum		= IPPROTO_GRE,
+	.me			= THIS_MODULE,
 	.manip_pkt		= gre_manip_pkt,
 	.in_range		= gre_in_range,
 	.unique_tuple		= gre_unique_tuple,