RDMA/hns: Refactor extend link table allocation

mainline inclusion
from mainline-v5.12-rc1
commit b6989da8
category: bugfix
bugzilla: 174002
CVE:NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b6989da85a27568088c91d3c8184050cf073a4fc

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The timeout link table works in HIP08 ES version and the hns driver only
support the CS version for HIP08, so delete the related code. Then
simplify the buffer allocation for link table to make the code more
readable.

Link: https://lore.kernel.org/r/1621481751-27375-1-git-send-email-liweihang@huawei.com


Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.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>