arm: dts: kirkwood*.dts: use SPDX-License-Identifier for board using GPL-2.0+

Follow the recent trend for the license description
Acked-by: NJason Cooper <jason@lakedaemon.net>
Signed-off-by: NGregory CLEMENT <gregory.clement@bootlin.com>

arch/arm/boot/dts/kirkwood-b3.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree file for Excito Bubba B3
  *
  * Copyright (C) 2013, Andrew Lunn <andrew@lunn.ch>
  *
- * 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 of the License, or (at your option) any later version.
  *
  * Note: This requires a new'ish version of u-boot, which disables the
  * L2 cache. If your B3 silently fails to boot, u-boot is probably too

arch/arm/boot/dts/kirkwood-blackarmor-nas220.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree file for Seagate Blackarmor NAS220
  *
  * Copyright (C) 2014 Evgeni Dobrev <evgeni@studio-punkt.com>
- *
- * Licensed under GPLv2 or later.
  */
 
 /dts-v1/;

arch/arm/boot/dts/kirkwood-netgear_readynas_duo_v2.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree file for NETGEAR ReadyNAS Duo v2
  *
  * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
- *
- * 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 of the License, or (at your option) any later version.
  */
 
 /dts-v1/;

arch/arm/boot/dts/kirkwood-netgear_readynas_nv+_v2.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree file for NETGEAR ReadyNAS NV+ v2
  *
  * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
- *
- * 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 of the License, or (at your option) any later version.
  */
 
 /dts-v1/;

arch/arm/boot/dts/kirkwood-nsa320.dts

+// SPDX-License-Identifier: GPL-2.0+
 /* Device tree file for the Zyxel NSA 320 NAS box.
  *
  * Copyright (c) 2014, Adam Baker <linux@baker-net.org.uk>
  *
- * 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 of the License, or (at your option) any later version.
  *
  * Based upon the board setup file created by Peter Schildmann */
 

arch/arm/boot/dts/kirkwood-nsa325.dts

+// SPDX-License-Identifier: GPL-2.0+
 /* Device tree file for the Zyxel NSA 325 NAS box.
  *
  * Copyright (c) 2015, Hans Ulli Kroll <ulli.kroll@googlemail.com>
  *
- * 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 of the License, or (at your option) any later version.
  *
  * Based upon the board setup file created by Peter Schildmann
  */

arch/arm/boot/dts/kirkwood-ts419-6281.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree file for QNAP TS41X with 6281 SoC
  *
  * Copyright (C) 2013, Andrew Lunn <andrew@lunn.ch>
- *
- * 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 of the License, or (at your option) any later version.
  */
 
 /dts-v1/;

arch/arm/boot/dts/kirkwood-ts419-6282.dts

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree file for QNAP TS41X with 6282 SoC
  *
  * Copyright (C) 2013, Andrew Lunn <andrew@lunn.ch>
- *
- * 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 of the License, or (at your option) any later version.
  */
 
 /dts-v1/;

arch/arm/boot/dts/kirkwood-ts419.dtsi

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Device Tree include file for QNAP TS41X
  *
  * Copyright (C) 2013, Andrew Lunn <andrew@lunn.ch>
- *
- * 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 of the License, or (at your option) any later version.
  */
 
 / {