RDMA/hns: Clear remaining unused sges when post_recv

mainline inclusion
from mainline-v5.12-rc1
commit 6b981e2b
category: bugfix
bugzilla: 174002
CVE:NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6b981e2bd9251f4f4d0fe32b1eeb29b0d88813a5

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The HIP09 requires the driver to clear the unused data segments in wqe
buffer to make the hns ROCEE stop reading the remaining invalid sges for
RQ.

Link: https://lore.kernel.org/r/1611997090-48820-11-git-send-email-liweihang@huawei.com


Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: wangsirong <wangsirong@huawei.com>
Reviewed-by: ChunZhi Hu <huchunzhi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>