PowerManager: Don't wake up device when charger is plugged/unplugged (1/2)

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

Change-Id: I3367041a05931510f367dafe412b173c80b89df1
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>