gpio: mxs: Fix header comment

This driver is about MXS GPIO support. MXC is a different platform.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: NBartosz Golaszewski <brgl@bgdev.pl>

drivers/gpio/gpio-mxs.c

 // SPDX-License-Identifier: GPL-2.0+
 //
-// MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
+// MXS GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
 // Copyright 2008 Juergen Beisert, kernel@pengutronix.de
 //
 // Based on code from Freescale,