net: hns3: adjust the timing of hns3_client_stop when unloading

hns3_client_stop() should be called after unregister_netdev(),
otherwise the ongoing reset task may start the client just after it.

Fixes: a6d818e3 ("net: hns3: Add vport alive state checking support")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>