tx5 only recognizes six response targets, drops all others

tx5 matches responses only for port 0, port 7, and port 1 cores 0-3 (matched on address and sub-address). Any response addressed to another port is silently ignored with no error. This is harmless today because tx5 only sends to those six targets, but it breaks scheduler responses for any other port in an 8- or 16-port configuration.