CpuGovernorService for all, optional iobusy server thread

This is not QCOM specific, enable the feature for all

- Disable easily the iowait busy feature by a flag
This sysfs ondemand feature requires kernel >= 2.6.35

- Add a DBG flag to remove the on/off spams, only keep the notifications
I/CpuGovernorService( 2332): intent action: android.intent.action.SCREEN_ON
I/CpuGovernorService( 2332): intent action: android.intent.action.SCREEN_OFF

Change-Id: Ib1b393caaa5608f54cc8525ea3657fcab0dbf7fe