alx: add alx_get_stats64 operation

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/alx/alx.h

@@ -106,6 +106,9 @@ struct alx_priv {
 	u16 msg_enable;
 
 	bool msi;
+
+	/* protects hw.stats */
+	spinlock_t stats_lock;
 };
 
 extern const struct ethtool_ops alx_ethtool_ops;