cpufreq: powernv: Free 'chips' on module exit

This will free the dynamically allocated memory of 'chips' on
module exit.

Signed-off-by: Shilpasri G Bhat <[e-mail]>
Reviewed-by: Gautham R. Shenoy <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/cpufreq/powernv-cpufreq.c

···
 	unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
 	opal_message_notifier_unregister(OPAL_MSG_OCC,
 					 &powernv_cpufreq_opal_nb);
+	kfree(chips);
 	cpufreq_unregister_driver(&powernv_cpufreq_driver);
 }
 module_exit(powernv_cpufreq_exit);