AntennaTracker: Ignore POSITION_TARGET_GLOBAL_INT

AntennaTracker/GCS_Mavlink.cpp

@@ -281,6 +281,7 @@ bool GCS_MAVLINK::try_send_message(enum ap_message id)
     case MSG_VIBRATION:
     case MSG_RPM:
     case MSG_MISSION_ITEM_REACHED:
+    case MSG_POSITION_TARGET_GLOBAL_INT:
         break; // just here to prevent a warning
     }
     return true;