RDMA/hns: Remove some redundant variables related to capabilities

In struct hns_roce_caps, max_srq_sg and max_srqwqes is unused, and
max_srqs has the same effect with num_srqs. So remove them from this
structrue.

Link: https://lore.kernel.org/r/1578738761-3176-2-git-send-email-liweihang@huawei.com


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