mgcp: Store one more codec/payload type if it is present

In case of some RTP proxy from time to time we are offered both
G729 and G711 but only one of them will work. I intend to adjust
the codec at runtime in case we receive the wrong codec.
diff --git a/openbsc/tests/mgcp/mgcp_test.ok b/openbsc/tests/mgcp/mgcp_test.ok
index 033f783..a56a3fd 100644
--- a/openbsc/tests/mgcp/mgcp_test.ok
+++ b/openbsc/tests/mgcp/mgcp_test.ok
@@ -474,4 +474,5 @@
 In TS: 160320, dTS: 160, Seq: 1002
 Out TS change: 160, dTS: 160, Seq change: 1, TS Err change: in +0, out +0
 Stats: Jitter = 0, Transit = -144000
+Testing multiple payload types
 Done