RDMA/hns: Fix accessing invalid dip_ctx during destroying QP

RDMA/hns: Fix accessing invalid dip_ctx during destroying QP

If it fails to modify QP to RTR, dip_ctx will not be attached. And
during detroying QP, the invalid dip_ctx pointer will be accessed.

Fixes: faa62440a577 ("RDMA/hns: Fix different dgids mapping to the same dip_idx")
Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20241220055249.146943-3-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>