gsm48: factor out MCC+MNC BCD parsing for re-use in UMTS

For 3G, I need a BCD composer/parser similar to gsm48_generate_lai()/
gsm48_decode_lai(). Those functions also handle a trivial extra
member (lac) which I don't need in this way for 3G.

So create new functions to take on the MCC+MNC BCD handling and call those
from gsm48_generate_lai() and gsm48_decode_lai(). In this way, the 3G code
in openbsc can use only the BCD functionality without code duplication.
3 files changed