treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_406.RULE

Based on the normalized pattern:

    this file is licensed under the term of the gnu general public license
    version 2 the program licensed as is without any warranty of any kind
    whether express or implied

extracted by the scancode license scanner the SPDX license identifier

    GPL-2.0-only

has been chosen to replace the boilerplate/reference.

Reviewed-by: Allison Randal <allison@lohutok.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: KAGA-KOKO

drivers/dma/ppc4xx/dma.h

@@ -1,13 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * 440SPe's DMA engines support header file
  *
  * 2006-2009 (C) DENX Software Engineering.
  *
  * Author: Yuri Tikhonov <yur@emcraft.com>
- *
- * This file is licensed under the term of  the GNU General Public License
- * version 2. The program licensed "as is" without any warranty of any
- * kind, whether express or implied.
  */
 
 #ifndef	_PPC440SPE_DMA_H

drivers/dma/ppc4xx/xor.h

@@ -1,13 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * 440SPe's XOR engines support header file
  *
  * 2006-2009 (C) DENX Software Engineering.
  *
  * Author: Yuri Tikhonov <yur@emcraft.com>
- *
- * This file is licensed under the term of  the GNU General Public License
- * version 2. The program licensed "as is" without any warranty of any
- * kind, whether express or implied.
  */
 
 #ifndef _PPC440SPE_XOR_H