intel_menlo: extract return values using PTR_ERR

Need to extract errors using PTR_ERR macro and
process accordingly.thermal_cooling_device_register
returning NULL means that CONFIG_THERMAL=n and in that
case no need to create symbolic links.
Signed-off-by: Thomas Sujith <sujith.thomas@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/misc/intel_menlow.c

@@ -170,10 +170,13 @@ static int intel_menlow_memory_add(struct acpi_device *device)
 
 	cdev = thermal_cooling_device_register("Memory controller", device,
 					       &memory_cooling_ops);
-	acpi_driver_data(device) = cdev;
-	if (!cdev)
-		result = -ENODEV;
-	else {
+	if (IS_ERR(cdev)) {
+		result = PTR_ERR(cdev);
+		goto end;
+	}
+
+	if (cdev) {
+		acpi_driver_data(device) = cdev;
 		result = sysfs_create_link(&device->dev.kobj,
 					&cdev->device.kobj, "thermal_cooling");
 		if (result)