RDMA/hns: Adjust fields and variables about CMDQ tail/head

mainline inclusion
from mainline-v5.12-rc1
commit 292b3352
category: bugfix
bugzilla: 174002
CVE:NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=292b3352bd5bd0abeba3e8e7b5ae5acb8f7df4e0

----------------------------------------------------------------------

The register 0x07014 is actually the head pointer of CMDQ, and 0x07010
means tail pointer. Current definitions are confusing, so rename them and
related variables.

The next_to_use of structure hns_roce_v2_cmq_ring has the same semantics
as head, merge them into one member. The next_to_clean of structure
hns_roce_v2_cmq_ring has the same semantics as tail. After deleting
next_to_clean, tail should also be deleted.

Link: https://lore.kernel.org/r/1612688143-28226-5-git-send-email-liweihang@huawei.com


Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: wangsirong <wangsirong@huawei.com>
Reviewed-by: ChunZhi Hu <huchunzhi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>