overlay: Remove usage of scale header

Remove usage of scale header and do not create or destroy objects.
the programScale() function exported out of libscale.so will
internally manage objects.

This frees up overlay from relying on scale.h which may not be
exported by libscale.so to a known location if only binaries are
shipped.

Change-Id: If6970541e2eb0ee2bdb907c73ed3534fc22e9dd1
4 files changed