in mgcp_codec.c we have a function mgcp_codec_pt_translate that is used
to find the equivalent payload type number on an opposite connection.
This is quite specific and the resulting payload type number may still
belong to a codec that might require some form of conversion.
Lets refactor this so that the function just finds a convertible codec
for a given connection. This also opens up other usecases. The payload
type conversion like we did it before can then be done with a few lines
in mgcp_network.c
Related: OS#5461
Change-Id: I085260a2ca8cfecdb58656b7a046c536189e238d
Philipp Maier
9dd80ca1f8