neigh: no need to call lookup_neigh_parms in neigh_parms_alloc

neigh_table.parms always exist and is initialized,kmemdup
can use it to create new neigh_parms, actually lookup_neigh_parms
here will return neigh_table.parms too.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/neighbour.c

@@ -1429,15 +1429,11 @@ static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,
 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 				      struct neigh_table *tbl)
 {
-	struct neigh_parms *p, *ref;
+	struct neigh_parms *p;
 	struct net *net = dev_net(dev);
 	const struct net_device_ops *ops = dev->netdev_ops;
 
-	ref = lookup_neigh_parms(tbl, net, 0);
-	if (!ref)
-		return NULL;
-
-	p = kmemdup(ref, sizeof(*p), GFP_KERNEL);
+	p = kmemdup(&tbl->parms, sizeof(*p), GFP_KERNEL);
 	if (p) {
 		p->tbl		  = tbl;
 		atomic_set(&p->refcnt, 1);