RDMA/hns: Support flexible pagesize for MTR

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5Y79T



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

In the current implementation, we use a fixed page size to
configure the MTR, which is not flexible enough and is not
conducive to the performance of the HW.

Now the best page size will be calculated and used to configure
the MTR. It only works for PBL now.

Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Reviewed-by: Yangyang Li <liyangyang20@huawei.com>
Reviewed-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>