ASoC: imx-pcm: 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/imx-pcm.h

+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
  *
  * This code is based on code copyrighted by Freescale,
  * Liam Girdwood, Javier Martin and probably others.
- *
- * 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.
  */
 
 #ifndef _IMX_PCM_H