atl1: update statistics code

As Ben Hutchings pointed out for the stats in alx, some
hardware-specific stats aren't matched to the right net_device_stats
field. Also fix the collision field and include errors in the total
number of RX/TX packets. Add a rx_dropped field and use it where
netdev->stats was modified directly out of the stats update function.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/atlx/atl1.h

@@ -666,6 +666,7 @@ struct atl1_sft_stats {
 	u64 rx_errors;
 	u64 rx_length_errors;
 	u64 rx_crc_errors;
+	u64 rx_dropped;
 	u64 rx_frame_errors;
 	u64 rx_fifo_errors;
 	u64 rx_missed_errors;