RDMA/hns: Fix Use-After-Free of rsv_qp on HIP08

RDMA/hns: Fix Use-After-Free of rsv_qp on HIP08

Currently rsv_qp is freed before ib_unregister_device() is called
on HIP08. During the time interval, users can still dereg MR and
rsv_qp will be used in this process, leading to a UAF. Move the
release of rsv_qp after calling ib_unregister_device() to fix it.

Fixes: 70f92521584f ("RDMA/hns: Use the reserved loopback QPs to free MR before destroying MPT")
Signed-off-by: wenglianfa <wenglianfa@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20240906093444.3571619-3-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>