net: hns3: Fix loss of coal configuration while doing reset

The user's coal configuration will be lost after reset, so the tx_coal
and rx_coal fields are added to the struct hns_nic_priv to save the coal
configuration and used to restore the user's configuration after the reset
is complete.

Fixes: bb6b94a8 ("net: hns3: Add reset interface implementation in client")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>