net: hns3: add or modify some comments

This patch makes the comment for macro HCLGE_MBX_GET_VF_FLR_STATUS
more correct, and adds comments in some place to make the code more
readable.

Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>