vxlan: Fix bug introduced by commit acbf74a7

Commit acbf74a7 ("vxlan: Refactor vxlan driver to make use of the common UDP tunnel functions." introduced a bug in vxlan_xmit_one()
function, causing it to transmit Vxlan packets without proper
Vxlan header inserted. The change was not needed in the first
place. Revert it.
Reported-by: Tom Herbert <therbert@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -1778,11 +1778,11 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
 		ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
 
-		err = udp_tunnel_xmit_skb(vxlan->vn_sock->sock, rt, skb,
-					  fl4.saddr, dst->sin.sin_addr.s_addr,
-					  tos, ttl, df, src_port, dst_port,
-					  !net_eq(vxlan->net,
-						  dev_net(vxlan->dev)));
+		err = vxlan_xmit_skb(vxlan->vn_sock, rt, skb,
+				     fl4.saddr, dst->sin.sin_addr.s_addr,
+				     tos, ttl, df, src_port, dst_port,
+				     htonl(vni << 8),
+				     !net_eq(vxlan->net, dev_net(vxlan->dev)));
 
 		if (err < 0)
 			goto rt_tx_error;