power: Tuning and cleanups

 * Tune the governor for better power usage and interactivity
 * Reset tuning parameters if governor changes
 * Cleanup

Change-Id: I56f5dcc7f15e5dfbcc38338d515fd41d04662ab1
power: Manage io_is_busy for interactive governor

Change-Id: I4591c7fb5c56353ff80c044f4c173216a9c29c1f