treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 220

Based on 1 normalized pattern(s):

distributed under the gnu gpl license version 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Allison Randal <[e-mail]>
Reviewed-by: Alexios Zavras <[e-mail]>
Reviewed-by: Steve Winslow <[e-mail]>
Reviewed-by: Kate Stewart <[e-mail]>
Cc: [e-mail]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/idr.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * include/linux/idr.h
  * 
  * 2002-10-18  written by Jim Houston [e-mail]
  *	Copyright (C) 2002 by Concurrent Computer Corporation
- *	Distributed under the GNU GPL license version 2.
  *
  * Small id to pointer translation service avoiding fixed sized
  * tables.