mmc: sdhci-esdhc-imx: 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: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-esdhc-imx.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Freescale eSDHC i.MX controller driver for the platform bus.
  *
@@ -5,10 +6,6 @@
  *
  * Copyright (c) 2010 Pengutronix e.K.
  *   Author: Wolfram Sang <kernel@pengutronix.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.
  */
 
 #include <linux/io.h>