ACPI: thermal: Check whether cooling device exists before unregistering

OS should check whether the cooling device exists before it is unregistered.
If it doesn't exists, it is unnecessary to remove the sysfs link
and call the function of thermal_cooling_device_unregister.

http://bugzilla.kernel.org/show_bug.cgi?id=9982Signed-off-by: NZhao Yakui <yakui.zhao@intel.com>
Tested-by    : Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/acpi/processor_core.c

@@ -809,10 +809,12 @@ static int acpi_processor_remove(struct acpi_device *device, int type)
 
 	acpi_processor_remove_fs(device);
 
-	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
-	sysfs_remove_link(&pr->cdev->device.kobj, "device");
-	thermal_cooling_device_unregister(pr->cdev);
-	pr->cdev = NULL;
+	if (pr->cdev) {
+		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+		sysfs_remove_link(&pr->cdev->device.kobj, "device");
+		thermal_cooling_device_unregister(pr->cdev);
+		pr->cdev = NULL;
+	}
 
 	processors[pr->id] = NULL;