RDMA/hns: Combine enable flags of qp

It's easier to understand and maintain enable flags of qp using a single
field in type of unsigned long than defining a field for every flags in
the structure hns_roce_qp, and we can add new flags for features more
conveniently in the future.

Link: https://lore.kernel.org/r/1588674607-25337-4-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@mellanox.com>