Input: atmel_mxt_ts - only allow root to update firmware

Restrict permissions on the update_fw sysfs entry to read only for root
only.

Also, update object permission to use a macro S_IRUGO macro instead of
hard coded 0444.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Joonyoung Shim <jy0922.shim@samsung.com>
Acked-by: Nick Dyer <nick.dyer@itdev.co.uk>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -1049,8 +1049,8 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR(object, 0444, mxt_object_show, NULL);
-static DEVICE_ATTR(update_fw, 0664, NULL, mxt_update_fw_store);
+static DEVICE_ATTR(object, S_IRUGO, mxt_object_show, NULL);
+static DEVICE_ATTR(update_fw, S_IWUSR, NULL, mxt_update_fw_store);
 
 static struct attribute *mxt_attrs[] = {
 	&dev_attr_object.attr,