hammerhead: add slim govenor

thanks a ton to flar2 where this govenor is based on. Small modifications done
and more will follow in future.

ToDo: we need to set the govenor as default as well other small modifications
to ramdisk

PS:
- cleanup

Change-Id: Ia7ea6714715103a24e0bbbddcff9e1d0e0771380