ASoC: mpc5200_dma: 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_dma.c

-/*
- * Freescale MPC5200 PSC DMA
- * ALSA SoC Platform driver
- *
- * Copyright (C) 2008 Secret Lab Technologies Ltd.
- * Copyright (C) 2009 Jon Smirl, Digispeaker
- */
+// SPDX-License-Identifier: GPL
+//
+// Freescale MPC5200 PSC DMA
+// ALSA SoC Platform driver
+//
+// Copyright (C) 2008 Secret Lab Technologies Ltd.
+// Copyright (C) 2009 Jon Smirl, Digispeaker
 
 #include <linux/module.h>
 #include <linux/of_device.h>