power: Add support for POWER_HINT_LOW_POWER

 * Just call set_power_profile
 * Also clean up all the warnings

Change-Id: Ia42badac37815e29411ad135716a0f791a00c510
Merge branch 'cm-12.0' of https://github.com/CyanogenMod/android_device_qcom_common into cm-12.0