mogami: add power management

Change-Id: I50204461e0a0b9f71bcad97d24cdb615372f6397
mogami-common: some cleanup

* Move gsm feature xml from devices to mogami-common
* Added & fixed some comments to the source files

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: Ia30d6d6370f28d5f62fecafcadada17b0f84bad2