PowerManager: Don't wake up device when charger is plugged/unplugged (2/2)

This will add the option to disable waking up the device when a charger
is plugged or unplugged.

added as well config option to disable volume rocker wake for devices
which do not support it well

Change-Id: Idf37087b4cdee94c8557d67ab3d491d65bc60c36