RDMA/hns: Support congestion control algorithm parameter configuration

RDMA/hns: Support congestion control algorithm parameter configuration

hns RoCE supports 4 congestion control algorithms. Each algorihm
involves multiple parameters. Support configuring these parameters
by debugfs.

Here are some examples of this feature:

* The directory structure:
$ ls /sys/kernel/debug/hns_roce/0000\:35\:00.0/
dcqcn_cc_param  dip_cc_param  hc3_cc_param  ldcp_cc_param
$ ls /sys/kernel/debug/hns_roce/0000\:35\:00.0/dcqcn_cc_param/
ai  al  alp  ashift  cnp_time  f  g  lifespan  max_speed  tkp  tmp

* Read the value of a param:
$ cat /sys/kernel/debug/hns_roce/0000\:35\:00.0/dcqcn_cc_param/ai
1

* Set a new value for a param:
$ echo 2 > /sys/kernel/debug/hns_roce/0000\:35\:00.0/dcqcn_cc_param/ai

Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20260507012148.1079712-4-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>