[NETFILTER]: xtables: fixes warning on compilation of hashlimit

To use ipv6_find_hdr(), IP6_NF_IPTABLES is necessary.
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/xt_hashlimit.c

@@ -388,7 +388,7 @@ hashlimit_init_dst(struct xt_hashlimit_htable *hinfo, struct dsthash_dst *dst,
 			return 0;
 		nexthdr = skb->nh.iph->protocol;
 		break;
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 	case AF_INET6:
 		if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
 			memcpy(&dst->addr.ip6.dst, &skb->nh.ipv6h->daddr,