power: Add fastboot functionality

 * Fastboot optimizes simple power on/off by putting the system into the
   lowest possible power state without shutting down the hardware.
 * The framework will all out to the FastPowerOn app for simple power
   off, and enable airplane mode, shut off USB, stop all media, and kill
   all non-system processes.
 * When the power key is pressed, the system wakes up, radios are
   restored, USB is restored.
 * It looks exactly like a normal power cycle, but faster!
 * Reboot option retains normal behavior.
 * Full shutdown is possible by a long-press on power off.

Adapted from CodeAurora:

Adding Fast Power ON functionality

- Switch normal power off/on and fast power off/on based on user`s
selection on the Settings application.
- Add an intent to enter/exit fast power on state
- Handle power off button behaviour when in fast power on mode

PM: Implement Fast Power On - do not wake up on USB unplug event

Avoid wake up from deep sleep if we are in FPO mode and usb unplug event occurs.

Change-Id: Ia115190c546c56bb9010e6ef5e15376e9c49e034