net: convert __IPTUNNEL_XMIT() to an inline function

__IPTUNNEL_XMIT() is an ugly macro, convert it to a static
inline function, so make it more readable.

IPTUNNEL_XMIT() is unused, just remove it.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_vti.c

@@ -71,15 +71,6 @@ static int vti_tunnel_bind_dev(struct net_device *dev);
 #define for_each_ip_tunnel_rcu(start) \
 	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 
-/* often modified stats are per cpu, other are shared (netdev->stats) */
-struct pcpu_tstats {
-	u64	rx_packets;
-	u64	rx_bytes;
-	u64	tx_packets;
-	u64	tx_bytes;
-	struct	u64_stats_sync	syncp;
-};
-
 #define VTI_XMIT(stats1, stats2) do {				\
 	int err;						\
 	int pkt_len = skb->len;					\