ACPI processor: Remove unneeded cpuidle_unregister_driver call

Since commit 46bcfad7a819bd17ac4e831b04405152d59784ab registering
and unregistering cpuidle is done in processor_idle.c.
Unregistering via:
acpi_bus_unregister_driver(&acpi_processor_driver)
   -> acpi_processor_remove()
      -> acpi_processor_power_exit()

Remove not needed cpuidle_unregister_driver() call from
acpi_processor_exit

Signed-off-by: Thomas Renninger <trenn@suse.de>
CC: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/processor_driver.c

@@ -828,8 +828,6 @@ static void __exit acpi_processor_exit(void)
 
 	acpi_bus_unregister_driver(&acpi_processor_driver);
 
-	cpuidle_unregister_driver(&acpi_idle_driver);
-
 	return;
 }