vxlan: fix a shadow local variable

Commit 79b16aad
("udp_tunnel: Pass UDP socket down through udp_tunnel{, 6}_xmit_skb()")
introduce 'sk' but we already have one inner 'sk'.

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>

drivers/net/vxlan.c

@@ -1977,7 +1977,6 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else {
-		struct sock *sk = vxlan->vn_sock->sock->sk;
 		struct dst_entry *ndst;
 		struct flowi6 fl6;
 		u32 flags;