net: export netdev_stats_to_stats64

Some drivers use internal netdev stats member to store part of their
stats, yet advertize ndo_get_stats64() to implement some 64bit fields.

Allow them to use netdev_stats_to_stats64() helper to make the copy of
netdev stats before they compute their 64bit counters.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f1b7d03..4d279c5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2557,6 +2557,8 @@
 extern void		dev_mcast_init(void);
 extern struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
 					       struct rtnl_link_stats64 *storage);
+extern void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
+				    const struct net_device_stats *netdev_stats);
 
 extern int		netdev_max_backlog;
 extern int		netdev_tstamp_prequeue;