netfilter: conntrack: define variables exp_nat_nla_policy and any_addr with CONFIG_NF_NAT

gcc with W=1 and ! CONFIG_NF_NAT
net/netfilter/nf_conntrack_netlink.c:3463:32: error:
  ‘exp_nat_nla_policy’ defined but not used [-Werror=unused-const-variable=]
 3463 | static const struct nla_policy exp_nat_nla_policy[CTA_EXPECT_NAT_MAX+1] = {
      |                                ^~~~~~~~~~~~~~~~~~
net/netfilter/nf_conntrack_netlink.c:2979:33: error:
  ‘any_addr’ defined but not used [-Werror=unused-const-variable=]
 2979 | static const union nf_inet_addr any_addr;
      |                                 ^~~~~~~~

These variables use is controlled by CONFIG_NF_NAT, so should their definitions.
Signed-off-by: NTom Rix <trix@redhat.com>
Reviewed-by: NSimon Horman <simon.horman@corigine.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>

net/netfilter/nf_conntrack_netlink.c

@@ -2976,7 +2976,9 @@ static int ctnetlink_exp_dump_mask(struct sk_buff *skb,
 	return -1;
 }
 
+#if IS_ENABLED(CONFIG_NF_NAT)
 static const union nf_inet_addr any_addr;
+#endif
 
 static __be32 nf_expect_get_id(const struct nf_conntrack_expect *exp)
 {
@@ -3460,10 +3462,12 @@ ctnetlink_change_expect(struct nf_conntrack_expect *x,
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_NF_NAT)
 static const struct nla_policy exp_nat_nla_policy[CTA_EXPECT_NAT_MAX+1] = {
 	[CTA_EXPECT_NAT_DIR]	= { .type = NLA_U32 },
 	[CTA_EXPECT_NAT_TUPLE]	= { .type = NLA_NESTED },
 };
+#endif
 
 static int
 ctnetlink_parse_expect_nat(const struct nlattr *attr,