watchdog: max77620_wdt: constify platform_device_id

platform_device_id are not supposed to change at runtime. All functions
working with platform_device_id provided by <linux/platform_device.h>
work with const platform_device_id. So mark the non-const structs as
const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/max77620_wdt.c

@@ -201,7 +201,7 @@ static int max77620_wdt_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct platform_device_id max77620_wdt_devtype[] = {
+static const struct platform_device_id max77620_wdt_devtype[] = {
 	{ .name = "max77620-watchdog", },
 	{ },
 };