library/PCUIF_Types: make PCUIF version configurable

When changing the PCUIF, we have to maintain backwards compatibility
with the release versions of both osmo-pcu and osmo-bts, not only
with the recent master.  In order to achieve that, let's introduce
'mp_pcuif_version', so the PCUIF version can be adjusted.

Change-Id: I3cf7f908e606b91dd2cbddc168827dd074aed052
Related: SYS#4868, OS#4547
2 files changed