mgcp_sdp: restructure mgcp_write_response_sdp() (rtpmap)

The function mgcp_write_response_sdp() generates the rtpmap lines in the
sdp response. Since we will likely support multiple codecs we will need
to generate several rtpmap lines. Therefore it makes sense to split up
that part in a separate function without altering the overall
functionality (yet)

- add static function add_rtpmap() to generate the rtpmap.

Change-Id: I520e2d40fe6294c88bae63dfcbc5238ef98101e2
Related: OS#3442
1 file changed