platform/x86: ideapad-laptop: Switch touchpad attribute to be RO

For now let's restrict touchpad attribute to be read only.
We might revisit this in the future though.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/ideapad-laptop.c

@@ -453,7 +453,8 @@ static ssize_t touchpad_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR_RW(touchpad);
+/* Switch to RO for now: It might be revisited in the future */
+static DEVICE_ATTR_RO(touchpad);
 
 static struct attribute *ideapad_attributes[] = {
 	&dev_attr_camera_power.attr,