valueAsASubject to valueAsATopic inconsistency fix (#1260)

main/ZgatewayRTL_433.ino

@@ -50,7 +50,7 @@ void rtl_433_Callback(char* message) {
   }
 
   String topic = String(subjectRTL_433toMQTT);
-#  ifdef valueAsASubject
+#  if valueAsATopic
   String model = RFrtl_433_ESPdata["model"];
   String id = RFrtl_433_ESPdata["id"];
   if (model != 0) {