bssap: Use new DTAP DLCI helper fields from libosmocore

This is the only place where the entire dtap header is passed, where
the split between SAPI and CHAN is done. Other places in osmo-bsc pass
around a link_id integer containing everything, so leaving that out of
the scope for this patch.

The gsm0406_dlci_sapi_name() API was introduced in libosmocore 1.3.0,
and osmo-bsc currently requires libosmocore 1.4.0, so it means we are
not further restricting libosmocore dependency here by using it.

Change-Id: Ib72e2bda46e39d1075e4270ac5fa51df2f418164
1 file changed