Base structure for the hotplug
Add nr_running stats thank's to @faux123
Start working at the main function of the hotplug
Add plug in/out functions

And some little changes
Enhance boost for screen touched

Now we don't always plug in a core but set a threshold for it.
Add sys parameters support
Add screen off actions and fix trying to unplug cpu0

Screen off actions are implemented with powersuspend. Thank's to faux123
for his module.
Clean comment and use plug in frequency as idle threshold
Fix deadlock at screen on

And a small fix to avoid a work to be enqueued just after the queue has
been flushed
Disable show-p's msm_mpdecision as default