cpufreq: create a helper function to get CPU utilization. Picked from @stratosk

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
blu_plug: improvements and fixes
* Driver recode and rework
* Improve suspend/resume routines
* Improve load calculations and plu/unplug routines
* Better work and queue management
* Fix merge derps and unplug if down_timer_cnt is set lower than up_timer_cnt thanks @kagwind
* Use original stratosk load calculation, link to cpu governor
* Add debug stuff
* Add min_cpu_offscreen tunable
* Other  misc. that I forgot ;p