ACPI fan: 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/acpi/fan.c

@@ -256,22 +256,28 @@ static int acpi_fan_add(struct acpi_device *device)
 
 	cdev = thermal_cooling_device_register("Fan", device,
 						&fan_cooling_ops);
-	if (cdev)
+	if (IS_ERR(cdev)) {
+		result = PTR_ERR(cdev);
+		goto end;
+	}
+	if (cdev) {
 		printk(KERN_INFO PREFIX
 			"%s is registered as cooling_device%d\n",
 			device->dev.bus_id, cdev->id);
-	else
-		goto end;
-	acpi_driver_data(device) = cdev;
-	result = sysfs_create_link(&device->dev.kobj, &cdev->device.kobj,
-					"thermal_cooling");
-	if (result)
-		return result;
 
-	result = sysfs_create_link(&cdev->device.kobj, &device->dev.kobj,
-                                       "device");
-        if (result)
-                return result;
+		acpi_driver_data(device) = cdev;
+		result = sysfs_create_link(&device->dev.kobj,
+					   &cdev->device.kobj,
+					   "thermal_cooling");
+		if (result)
+			return result;
+
+		result = sysfs_create_link(&cdev->device.kobj,
+					   &device->dev.kobj,
+					   "device");
+		if (result)
+			return result;
+	}
 
 	result = acpi_fan_add_fs(device);
 	if (result)