mmc: mxcmmc: constify mxcmci_devtype

mxcmci_devtype struct contains constant data, so
constify this struct.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/mxcmmc.c

@@ -165,7 +165,7 @@ struct mxcmci_host {
 	enum mxcmci_type	devtype;
 };
 
-static struct platform_device_id mxcmci_devtype[] = {
+static const struct platform_device_id mxcmci_devtype[] = {
 	{
 		.name = "imx21-mmc",
 		.driver_data = IMX21_MMC,