RDMA/hns: Modify qp&cq&pd specification according to UM

Accroding to hip08's limitation, qp&cq specification is 1M, mtpt
specification 1M in kernel space.

Signed-off-by: Yangyang Li <liyangyang20@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>