regulator: vexpress: Switch to SPDX identifier

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/vexpress-regulator.c

-/*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * Copyright (C) 2012 ARM Limited
- */
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2012 ARM Limited
 
 #define DRVNAME "vexpress-regulator"
 #define pr_fmt(fmt) DRVNAME ": " fmt