So far, BSSMAP_Emulation used the SCCPasp_SP_PORT directly, explicitly
calling BSSAP encode/decode functions while processing the primitives.
Let's clean this up and use the BSSAP_CodecPort which has meanwhile
been developed as a dual-faced port that can be stacked between SCCPasp
and the user to avoid any manual encode/decode function calls.
Change-Id: Icded789d18f3469f74e16f552df2c7ac44ac4294