nfc: nci: replace GPLv2 boilerplate with SPDX

Replace standard GPLv2 license text with SPDX tag.  Although the comment
mentions GPLv2-only, it refers to the full license file which allows
later GPL versions.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/nfc/nci/uart.c

+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2015, Marvell International Ltd.
  *
- * This software file (the "File") is distributed by Marvell International
- * Ltd. under the terms of the GNU General Public License Version 2, June 1991
- * (the "License").  You may use, redistribute and/or modify this File in
- * accordance with the terms and conditions of the License, a copy of which
- * is available on the worldwide web at
- * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
- *
- * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
- * ARE EXPRESSLY DISCLAIMED.  The License provides additional details about
- * this warranty disclaimer.
- */
-
-/* Inspired (hugely) by HCI LDISC implementation in Bluetooth.
+ * Inspired (hugely) by HCI LDISC implementation in Bluetooth.
  *
  *  Copyright (C) 2000-2001  Qualcomm Incorporated
  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>