MT#56861 be more explicit with "inject DTMF" flag

Instead of just setting the "force transcoding" flag when DTMF injection
is required, check it on a per-codec basis, so we can be more granular
with this decision.

Functional no-op.

Change-Id: I496f3d1fba5840e7870c373f94190243392db438

daemon/codec.c

@@ -1110,8 +1110,6 @@ bool codec_handlers_update(struct call_media *receiver, struct call_media *sink,
 
 	// do we have to force everything through the transcoding engine even if codecs match?
 	bool force_transcoding = do_pcm_dtmf_blocking || do_dtmf_blocking || use_audio_player;
-	if (sink->monologue->inject_dtmf)
-		force_transcoding = true;
 
 	for (GList *l = receiver->codecs.codec_prefs.head; l; ) {
 		struct rtp_payload_type *pt = l->data;
@@ -1322,6 +1320,10 @@ sink_pt_fixed:;
 			}
 		}
 
+		// force transcoding if we want DTMF injection
+		if (sink->monologue->inject_dtmf)
+			goto transcode;
+
 		// everything matches - we can do passthrough
 		ilogs(codec, LOG_DEBUG, "Sink supports codec " STR_FORMAT " for passthrough",
 				STR_FMT(&pt->encoding_with_params));