topic_listener: avoid code generation, use existing metadata at runtime

This reduces flash size for v5 by ~110KB, the topic listener now only adds
about 1.2KB.

msg/templates/uorb/msg.h.em

@@ -133,5 +133,5 @@ ORB_DECLARE(@multi_topic);
 @[end for]
 
 #ifdef __cplusplus
-void print_message(const @uorb_struct& message);
+void print_message(const orb_metadata *meta, const @uorb_struct& message);
 #endif