ASoC: mpc5200_psc_ac97: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: Andra Danciu <andradanciu1997@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/mpc5200_psc_ac97.c

-/*
- * linux/sound/mpc5200-ac97.c -- AC97 support for the Freescale MPC52xx chip.
- *
- * Copyright (C) 2009 Jon Smirl, Digispeaker
- * Author: Jon Smirl <jonsmirl@gmail.com>
- *
- * 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.
- */
+// SPDX-License-Identifier: GPL-2.0
+//
+// linux/sound/mpc5200-ac97.c -- AC97 support for the Freescale MPC52xx chip.
+//
+// Copyright (C) 2009 Jon Smirl, Digispeaker
+// Author: Jon Smirl <jonsmirl@gmail.com>
 
 #include <linux/module.h>
 #include <linux/of_device.h>