RDMA/hns: Modify fields of struct hns_roce_srq

Use wqe_cnt instead of max which means the queue size of srq, and remove
wqe_ctr which is not used.

Link: https://lore.kernel.org/r/1572952082-6681-5-git-send-email-liweihang@hisilicon.com


Signed-off-by: Yixian Liu <liuyixian@huawei.com>
Signed-off-by: Weihang Li <liweihang@hisilicon.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>