dmaengine: imx-sdma: Switch to SPDX identifier

Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/imx-sdma.c

-/*
- * drivers/dma/imx-sdma.c
- *
- * This file contains a driver for the Freescale Smart DMA engine
- *
- * Copyright 2010 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
- *
- * Based on code from Freescale:
- *
- * Copyright 2004-2009 Freescale Semiconductor, Inc. All Rights Reserved.
- *
- * The code contained herein is licensed under the GNU General Public
- * License. You may obtain a copy of the GNU General Public License
- * Version 2 or later at the following locations:
- *
- * http://www.opensource.org/licenses/gpl-license.html
- * http://www.gnu.org/copyleft/gpl.html
- */
+// SPDX-License-Identifier: GPL-2.0+
+//
+// drivers/dma/imx-sdma.c
+//
+// This file contains a driver for the Freescale Smart DMA engine
+//
+// Copyright 2010 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+//
+// Based on code from Freescale:
+//
+// Copyright 2004-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 
 #include <linux/init.h>
 #include <linux/iopoll.h>