RDMA/hns: Remove the reserved WQE of SRQ

Each SRQs contain an reserved WQE, it is inappropriate and should be
removed.

Fixes: c7bcb134 ("RDMA/hns: Add SRQ support for hip08 kernel mode")
Link: https://lore.kernel.org/r/1611997090-48820-6-git-send-email-liweihang@huawei.com


Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>