RDMA/hns: Add method to detach WQE buffer

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I63KVU



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If a uQP works in DCA mode, the userspace driver needs to drop the WQE
buffer by calling the 'HNS_IB_METHOD_DCA_MEM_DETACH' method when the QP's
CI is equal to PI, that means, the hns ROCEE will not access the WQE's
buffer at this time, and the userspace driver can free this WQE's buffer.

This method will start an worker queue to recycle the WQE buffer in kernel
space, if the WQE buffer is indeed not being accessed by hns ROCEE, the
worker will change the pages' state as free in DCA memory pool.

Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Reviewed-by: Yangyang Li <liyangyang20@huawei.com>
Reviewed-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>