mobile: compose Bearer Capability IE depending on PHY capabilities and GAPK codec support
This was originally proposed as a checklist item in #3400. The idea is to compose the
Bearer Capability IE in Uplink
(CC) Setup messages not only based on the VTY configuration (see below), but also based on the PHY capabilities (see #1461) and GAPK codec support (see #3400). The respective function
mncc_set_bearer() can be found in https://cgit.osmocom.org/osmocom-bb/tree/src/host/layer23/src/mobile/mnccms.c.