net: make ndo_get_stats64 a void function

The network device operation for reading statistics is only called
in one place, and it ignores the return value. Having a structure
return value is potentially confusing because some future driver could
incorrectly assume that the return value was used.

Fix all drivers with ndo_get_stats64 to have a void function.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ppp/ppp_generic.c

@@ -1297,7 +1297,7 @@ ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	return err;
 }
 
-static struct rtnl_link_stats64*
+static void
 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
 {
 	struct ppp *ppp = netdev_priv(dev);
@@ -1317,8 +1317,6 @@ ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
 	stats64->rx_dropped       = dev->stats.rx_dropped;
 	stats64->tx_dropped       = dev->stats.tx_dropped;
 	stats64->rx_length_errors = dev->stats.rx_length_errors;
-
-	return stats64;
 }
 
 static int ppp_dev_init(struct net_device *dev)