net: hns3: Add packet statistics of netdev

Add packet statistics of netdev for ethtool -S, in
order to show the statistics data for current net
device.

Remove update_stats() calling because it has been
completed in hns3_get_netdev_stats().

Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>