cpufreq: add yankactive governor

Interactive governor with, fow now :

- hispeed_freq defaulting to lower than policy_max (1.73GHz)
- target_loads increased to 95
- min_sampling time reduced to 20ms
- above_hispeed_delay increased to 80ms
- timer_rate increased to 20ms

cpufreq: yankactive: Optimize sync_freq implementation

Don't let frequency drop below sync_freq if either load or
frequency among other cpus is above a certain threshold,
not necessarily both.

Credits : cyanogen