net: hns3: add hclge_cmd_check_retval() to parse comman's return value

For simplifying the code, this patch adds hclge_cmd_check_retval() to
check the return value of the command.

Also, according the IMP's description, when there are several descriptors
in a command, then the IMP will save the return value on the last
description, so hclge_cmd_check_retval() just check the last one for this
case.

Signed-off-by: Weihang Li <liweihang@hisilicon.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>