GPRS_Components: use more suitable SAPI for DL TBF assignment

The function that assigns the downlink TBF f_ms_exp_dl_tbf_ass_ccch()
uses SAPI PCU_IF_SAPI_AGCH as default but actually downlink TBFs are
assigned via the PCH. This means we have to put PCU_IF_SAPI_PCH into the
parameter list on every function call, so it makes sense to change the
default to PCU_IF_SAPI_PCH and omit the SAPI when calling the function

Related: OS#5927
Change-Id: I49c59bad0162cb303669f6108201f154918b1db3
2 files changed