treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 376

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 only
  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 4 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081036.798138318@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/hw_random/s390-trng.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * s390 TRNG device driver
  *
@@ -6,11 +7,6 @@
 
  * Copyright IBM Corp. 2017
  * Author(s): Harald Freudenberger <freude@de.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2 only)
- * as published by the Free Software Foundation.
- *
  */
 
 #define KMSG_COMPONENT "trng"

tools/perf/arch/s390/util/header.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Implementation of get_cpuid().
  *
  * Copyright IBM Corp. 2014, 2018
  * Author(s): Alexander Yarygin <yarygin@linux.vnet.ibm.com>
  *	      Thomas Richter <tmricht@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2 only)
- * as published by the Free Software Foundation.
  */
 
 #include <sys/types.h>

tools/perf/arch/s390/util/kvm-stat.c

+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Arch specific functions for perf kvm stat.
  *
  * Copyright 2014 IBM Corp.
  * Author(s): Alexander Yarygin <yarygin@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2 only)
- * as published by the Free Software Foundation.
  */
 
 #include <errno.h>