ip6_vti: Remove generic .ndo_get_stats64

Commit 3e2f544d ("net: get stats64 if device if driver is
configured") moved the callback to dev_get_tstats64() to net core, so,
unless the driver is doing some custom stats collection, it does not
need to set .ndo_get_stats64.

Since this driver is now relying in NETDEV_PCPU_STAT_TSTATS, then, it
doesn't need to set the dev_get_tstats64() generic .ndo_get_stats64
function pointer.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_vti.c

@@ -887,7 +887,6 @@ static const struct net_device_ops vti6_netdev_ops = {
 	.ndo_uninit	= vti6_dev_uninit,
 	.ndo_start_xmit = vti6_tnl_xmit,
 	.ndo_siocdevprivate = vti6_siocdevprivate,
-	.ndo_get_stats64 = dev_get_tstats64,
 	.ndo_get_iflink = ip6_tnl_get_iflink,
 };