netfilter: nf_tables: constify chain type definitions and pointers

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/ipv6/netfilter/nf_tables_ipv6.c b/net/ipv6/netfilter/nf_tables_ipv6.c
index a340276..758a32b 100644
--- a/net/ipv6/netfilter/nf_tables_ipv6.c
+++ b/net/ipv6/netfilter/nf_tables_ipv6.c
@@ -90,7 +90,7 @@
 	.exit	= nf_tables_ipv6_exit_net,
 };
 
-static struct nf_chain_type filter_ipv6 = {
+static const struct nf_chain_type filter_ipv6 = {
 	.family		= NFPROTO_IPV6,
 	.name		= "filter",
 	.type		= NFT_CHAIN_T_DEFAULT,
diff --git a/net/ipv6/netfilter/nft_chain_nat_ipv6.c b/net/ipv6/netfilter/nft_chain_nat_ipv6.c
index e86dcd7..efd1d57 100644
--- a/net/ipv6/netfilter/nft_chain_nat_ipv6.c
+++ b/net/ipv6/netfilter/nft_chain_nat_ipv6.c
@@ -170,7 +170,7 @@
 	return ret;
 }
 
-static struct nf_chain_type nft_chain_nat_ipv6 = {
+static const struct nf_chain_type nft_chain_nat_ipv6 = {
 	.family		= NFPROTO_IPV6,
 	.name		= "nat",
 	.type		= NFT_CHAIN_T_NAT,
diff --git a/net/ipv6/netfilter/nft_chain_route_ipv6.c b/net/ipv6/netfilter/nft_chain_route_ipv6.c
index 3fe40f0..3620f88 100644
--- a/net/ipv6/netfilter/nft_chain_route_ipv6.c
+++ b/net/ipv6/netfilter/nft_chain_route_ipv6.c
@@ -59,7 +59,7 @@
 	return ret;
 }
 
-static struct nf_chain_type nft_chain_route_ipv6 = {
+static const struct nf_chain_type nft_chain_route_ipv6 = {
 	.family		= NFPROTO_IPV6,
 	.name		= "route",
 	.type		= NFT_CHAIN_T_ROUTE,