regulator: fan53555: Switch to SPDX identifier

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/fan53555.c

-/*
- * FAN53555 Fairchild Digitally Programmable TinyBuck Regulator Driver.
- *
- * Supported Part Numbers:
- * FAN53555UC00X/01X/03X/04X/05X
- *
- * Copyright (c) 2012 Marvell Technology Ltd.
- * Yunfan Zhang <yfzhang@marvell.com>
- *
- * This package 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.
- *
- */
+// SPDX-License-Identifier: GPL-2.0
+//
+// FAN53555 Fairchild Digitally Programmable TinyBuck Regulator Driver.
+//
+// Supported Part Numbers:
+// FAN53555UC00X/01X/03X/04X/05X
+//
+// Copyright (c) 2012 Marvell Technology Ltd.
+// Yunfan Zhang <yfzhang@marvell.com>
+
 #include <linux/module.h>
 #include <linux/param.h>
 #include <linux/err.h>