netfilter: xtables: use NFPROTO_ for xt_proto_init callsites

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 2ec8d72..3051dda 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -2201,12 +2201,12 @@
 
 static int __net_init ip_tables_net_init(struct net *net)
 {
-	return xt_proto_init(net, AF_INET);
+	return xt_proto_init(net, NFPROTO_IPV4);
 }
 
 static void __net_exit ip_tables_net_exit(struct net *net)
 {
-	xt_proto_fini(net, AF_INET);
+	xt_proto_fini(net, NFPROTO_IPV4);
 }
 
 static struct pernet_operations ip_tables_net_ops = {