Tunneling: use IP Tunnel stats APIs.

Use common function get calculate rtnl_link_stats64 stats.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 053b53e..8603ca8 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -319,6 +319,7 @@
 config NET_IPVTI
 	tristate "Virtual (secure) IP: tunneling"
 	select INET_TUNNEL
+	select NET_IP_TUNNEL
 	depends on INET_XFRM_MODE_TUNNEL
 	---help---
 	  Tunneling means encapsulating data of one protocol type within