neigh: use tbl->family to distinguish ipv4 from ipv6

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 3a37c7d..f041858 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -1287,7 +1287,7 @@
 	dev_add_pack(&arp_packet_type);
 	arp_proc_init();
 #ifdef CONFIG_SYSCTL
-	neigh_sysctl_register(NULL, &arp_tbl.parms, "ipv4", NULL);
+	neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
 #endif
 	register_netdevice_notifier(&arp_netdev_notifier);
 }