RDMA/hns: Fix wrong timer context buffer page size

mainline inclusion
from mainline-v5.14
commit 5e6370d7
category: bugfix
bugzilla: NA
CVE: NA

The HEM page size for QPC timer and CQC timer is always 4K and there's no need to calculate a different size by the hns driver,
otherwise the ROCEE may access an invalid address.

Signed-off-by: Shunfeng Yang <yangshunfeng2@huawei.com>
Signed-off-by: Yangyang Li <liyangyang20@huawei.com>
Reviewed-by: chunzhi hu <huchunzhi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>