netfilter: x_tables: use NFPROTO_* in extensions

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv6/netfilter/ip6t_rt.c b/net/ipv6/netfilter/ip6t_rt.c
index 81aaf7a..7c544ae 100644
--- a/net/ipv6/netfilter/ip6t_rt.c
+++ b/net/ipv6/netfilter/ip6t_rt.c
@@ -214,7 +214,7 @@
 
 static struct xt_match rt_mt6_reg __read_mostly = {
 	.name		= "rt",
-	.family		= AF_INET6,
+	.family		= NFPROTO_IPV6,
 	.match		= rt_mt6,
 	.matchsize	= sizeof(struct ip6t_rt),
 	.checkentry	= rt_mt6_check,