neigh: remove dynamic neigh table registration support

Currently there are only three neigh tables in the whole kernel:
arp table, ndisc table and decnet neigh table. What's more,
we don't support registering multiple tables per family.
Therefore we can just make these tables statically built-in.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index dedfb18..eb070b3 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -220,6 +220,13 @@
 	struct pneigh_entry	**phash_buckets;
 };
 
+enum {
+	NEIGH_ARP_TABLE = 0,
+	NEIGH_ND_TABLE = 1,
+	NEIGH_DN_TABLE = 2,
+	NEIGH_NR_TABLES,
+};
+
 static inline int neigh_parms_family(struct neigh_parms *p)
 {
 	return p->tbl->family;
@@ -240,8 +247,8 @@
 #define NEIGH_UPDATE_F_ISROUTER			0x40000000
 #define NEIGH_UPDATE_F_ADMIN			0x80000000
 
-void neigh_table_init(struct neigh_table *tbl);
-int neigh_table_clear(struct neigh_table *tbl);
+void neigh_table_init(int index, struct neigh_table *tbl);
+int neigh_table_clear(int index, struct neigh_table *tbl);
 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 			       struct net_device *dev);
 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,