[NETFILTER]: annotate rest of nf_nat_* with const

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index 0d5fa3a..9c8aa8d 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -150,9 +150,9 @@
 		     const struct nf_nat_range *range)
 {
 	unsigned int h = hash_by_src(tuple);
-	struct nf_conn_nat *nat;
-	struct nf_conn *ct;
-	struct hlist_node *n;
+	const struct nf_conn_nat *nat;
+	const struct nf_conn *ct;
+	const struct hlist_node *n;
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(nat, n, &bysource[h], bysource) {
@@ -426,7 +426,7 @@
 		struct icmphdr icmp;
 		struct iphdr ip;
 	} *inside;
-	struct nf_conntrack_l4proto *l4proto;
+	const struct nf_conntrack_l4proto *l4proto;
 	struct nf_conntrack_tuple inner, target;
 	int hdrlen = ip_hdrlen(skb);
 	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);