mgcp_sdp: restructure mgcp_write_response_sdp() (audio)

The function mgcp_write_response_sdp() is responsible to write the
audio port and the list with the supported payload type numbers to
the sdp response. At the moment it can only write exactly one payload
type number to the response, but in the future we may want to write
several payload type numbers to the response. Lets add a function
for that so that now.

- add add_audio() helper function to add multiple payload type
  numbers, but keep the functionality as it is for now

Change-Id: I662c725f697b2ffb1e3ad4671a445f943cd79b63
Related: OS#3442
1 file changed