RDMA/hfi1: Convert to SPDX identifier

use SPDX-License-Identifier instead of a verbose license text

Link: https://lore.kernel.org/r/20210823042622.109-1-caihuoqing@baidu.com


Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>