gsm_data: use feature list from libosmocore

In order to avoid code duplication the feature list (bit masks) and
the desciptive value strings as well as the function to set and get
the feature bits have been moved to libosmocore.

- use feature list functionality provided by libosmocore

Depends: libosmocore Change-Id Id0c35aef11aa49aa40abe7deef1f9dbd12210776
Change-Id: I3e80517539cc5d0e5d8189d434a5e3cc0fdea1a0
9 files changed