PowerHAL highlights:
* The CPU governor is always interactive. Governor changes are not
expected and permissions are set once on boot.
* Powersave profile: the CPU frequency is limited 787MHz and the CPU
is never boosted on user interaction. This will save power without
making the phone unbearably slow.
* Performance profile: the CPU is constantly boosted.
* Balanced profile: the CPU is boosted on user interaction.
When the screen is turned off, the governor is tuned to lower the
power consumption to save power in case of long lasting screen off
activities such as music playback.
* Currently there are no restrictions on the number of active cores.
With this PowerHAL cpu-boost is not needed, so keep it disabled.
In addition to that, drop all the properties based profiles and set
config_perf_profile_prop to "powerhal" to make the framework send
hints to PowerHAL when the power profile is changed.
msm8226-common: PowerHAL: Initialize mutex
Since the mutex is declared as static, this went unnoticed, but mutexes
should always be initialized, so do it.
msm8226-common: PowerHAL: Don't override user selected profiles
Save and restore the last selected profile so that the user preference
is not lost when transitioning out the low power mode. Also, don't
actually change the profile if in low power mode, but don't discard
the user preference.
msm8226-common: Refactor PowerHAL
Make the HAL generic by keeping the device dependent configuration
separate. This allows to easily add or edit the profiles.
The HAL should behave exactly as before, except for the fact that now
there might be some useless writes when the screen is turned off.
Change-Id: I6bb01a14f0058c59986989568e7766f4203150cc
