RDMA/hns: Add clear_hem return value to log

Log return value of clear_hem() to help diagnose.

Link: https://lore.kernel.org/r/20230523121641.3132102-4-huangjunxian6@hisilicon.com


Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>