mncc: Complete definitions for all speech traffic frames at MNCC interface

The new definitions are: half rate and AMR

Change of definition name for bad frame, because it applies to all types of
traffic, not only TCH/F.

Increase MNCC interface version to 4. Version 3 is skipped, because it was
used by older version of Linux-Call-Router which is incompatible with the
current version of the MNCC interface.
diff --git a/openbsc/src/libtrau/trau_mux.c b/openbsc/src/libtrau/trau_mux.c
index 7b9bac0..fd1895f 100644
--- a/openbsc/src/libtrau/trau_mux.c
+++ b/openbsc/src/libtrau/trau_mux.c
@@ -314,7 +314,7 @@
 	return msg;
 
 bad_frame:
-	frame->msg_type = GSM_TCHF_BAD_FRAME;
+	frame->msg_type = GSM_BAD_FRAME;
 
 	return msg;
 }