vfio: platform: reset: Convert to SPDX identifier

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

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20210822043643.2040-1-caihuoqing@baidu.com


Signed-off-by: Alex Williamson <alex.williamson@redhat.com>