net/mlx5e: IPoIB, Add ndo stats support for IPoIB child devices

mainline inclusion
from mainline-4.20
commit b75ba3822c61
category: bugfix
bugzilla: 6101
CVE: NA

-------------------------------------------------

Expose RX and TX counters by implementing ndo_get_stats64 operation
for child devices.
Signed-off-by: NFeras Daoud <ferasda@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NKeefe LIU <liuqifa@huawei.com>
Reviewed-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib_vlan.c

@@ -146,6 +146,7 @@ static const struct net_device_ops mlx5i_pkey_netdev_ops = {
 	.ndo_open                = mlx5i_pkey_open,
 	.ndo_stop                = mlx5i_pkey_close,
 	.ndo_init                = mlx5i_pkey_dev_init,
+	.ndo_get_stats64         = mlx5i_get_stats,
 	.ndo_uninit              = mlx5i_pkey_dev_cleanup,
 	.ndo_change_mtu          = mlx5i_pkey_change_mtu,
 	.ndo_do_ioctl            = mlx5i_pkey_ioctl,