RDMA/hns: Use flush framework for the case in aeq

As now we already have flush framework, using it instead of current flush
process for qp error in asynchronized interrupt (aeq).

Link: https://lore.kernel.org/r/1582367158-27030-2-git-send-email-liuyixian@huawei.com


Signed-off-by: Yixian Liu <liuyixian@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>