net: hns3: refactor the statistics updating for netdev

In origin codes, there are some statistics item are got from mac, which
also include the packets statistics of VF. It is unreasonable. This
patch fixes it by counting them in the rx/tx processing flow.

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