No osmux specific code in place during codec negotiation
Current code in OsmoBSC and OsmoMSC doesn't take into account that Osmux is to be used when codec negotiation goes one. That means that supported codec list needs to be correctly configured manually in VTY in order to avoid selecting incorrect codecs (like non-AMR). Moreover if an MS doesn't support AMR, since we don't have transcoding yet, the call cannot take place.
Different scenarios need to be listed here and think about what we want to do in each case.