mgcp_codec: move mgcp_codec_decide down

In a follow up patch we intend to fix mgcp_codec_decide, since the
fixed version of mgcp_codec_decide will use some functions below its
current position let's move it down before fixing it to make reviewing
the changes easier.

Related: OS#5461
Change-Id: I2f2538ff912eae4d80d3b74b766e18c4da94d6b6
1 file changed