ASoC: imx-audmux: 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-audmux.c

-/*
- * Copyright 2012 Freescale Semiconductor, Inc.
- * Copyright 2012 Linaro Ltd.
- * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
- *
- * Initial development of this code was funded by
- * Phytec Messtechnik GmbH, http://www.phytec.de
- *
- * 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.
- *
- * 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.
- */
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright 2012 Freescale Semiconductor, Inc.
+// Copyright 2012 Linaro Ltd.
+// Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
+//
+// Initial development of this code was funded by
+// Phytec Messtechnik GmbH, http://www.phytec.de
 
 #include <linux/clk.h>
 #include <linux/debugfs.h>