RDMA/hns: Change variables representing quantity to unsigned

Number of sge/eqe is always non-negative, they should be defined in type
of unsigned.

Link: https://lore.kernel.org/r/1589982799-28728-8-git-send-email-liweihang@huawei.com


Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>