treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 403

Based on 1 normalized pattern(s):

this software may be redistributed and or modified under the terms
of the gnu general public license gpl version 2 as published by the
free software foundation

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: Armijn Hemel <[e-mail]>
Cc: [e-mail]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

mm/dmapool.c

···
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * DMA Pool allocator
  *
  * Copyright 2001 David Brownell
  * Copyright 2007 Intel Corporation
  *   Author: Matthew Wilcox <[e-mail]>
- *
- * This software may be redistributed and/or modified under the terms of
- * the GNU General Public License ("GPL") version 2 as published by the
- * Free Software Foundation.
  *
  * This allocator returns small blocks of a given size which are DMA-able by
  * the given device.  It uses the dma_alloc_coherent page allocator to get