neigh: Don't require a dst in neigh_resolve_output

Having a dst helps a little bit for teql but is fundamentally
unnecessary and there are code paths where a dst is not available that
it would be nice to use the neighbour cache.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/neighbour.c

@@ -1284,12 +1284,8 @@ static void neigh_hh_init(struct neighbour *n)
 
 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb)
 {
-	struct dst_entry *dst = skb_dst(skb);
 	int rc = 0;
 
-	if (!dst)
-		goto discard;
-
 	if (!neigh_event_send(neigh, skb)) {
 		int err;
 		struct net_device *dev = neigh->dev;
@@ -1312,8 +1308,6 @@ int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb)
 	}
 out:
 	return rc;
-discard:
-	neigh_dbg(1, "%s: dst=%p neigh=%p\n", __func__, dst, neigh);
 out_kfree_skb:
 	rc = -EINVAL;
 	kfree_skb(skb);