RDMA/hns: Bugfix for cleaning mtr

It uses hns_roce_mtr_init in hns_roce_create_qp_common function.  As a
result, it should use hns_roce_mtr_cleanup function for cleaning mtr when
destroying qp.

Fixes: 8d18ad83 ("RDMA/hns: Fix bug when wqe num is larger than 16K")
Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>