net: hns3: add initialization for nic state

This patch adds initialization for nic state, sets flag
HNS3_NIC_STATE_DOWN when initialize, clears it before
vectors and napi being enabled in the hns3_nic_net_up(),
and sets it back in the error handler.

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