scsi: sg: switch to SPDX tags

Use the the GPLv2+ SPDX tag instead of verbose boilerplate text.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sg.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  *  History:
  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
@@ -8,12 +9,6 @@
  *        Copyright (C) 1992 Lawrence Foard
  * Version 2 and 3 extensions to driver:
  *        Copyright (C) 1998 - 2014 Douglas Gilbert
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
  */
 
 static int sg_version_num = 30536;	/* 2 digits for each component */