net: hns3: refactor out hclge_cmd_convert_err_code()

To improve code readability and maintainability, refactor
hclge_cmd_convert_err_code() with an array of imp_errcode
and common_errno mapping, instead of a bloated switch/case.

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>