RDMA/hns: Fix wrong timer context buffer page size

RDMA/hns: Fix wrong timer context buffer page size

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.

Fixes: 719d13415f59 ("RDMA/hns: Remove duplicated hem page size config code")
Link: https://lore.kernel.org/r/1621589395-2435-4-git-send-email-liweihang@huawei.com
Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>