RDMA/hns: Allocate one more recv SGE for HIP08

The RQ/SRQ of HIP08 needs one special sge to stop receive reliably. So the
driver needs to allocate at least one SGE when creating RQ/SRQ and ensure
that at least one SGE is filled with the special value during post_recv.

Besides, the kernel driver should only do this for kernel ULP. For
userspace ULP, the userspace driver will allocate the reserved SGE in
buffer, and the kernel driver just needs to pin the corresponding size of
memory based on the userspace driver's requirements.

Link: https://lore.kernel.org/r/1611997090-48820-2-git-send-email-liweihang@huawei.com


Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>