Sub: adjust for new update entry points into GCS

ArduSub/ArduSub.cpp

@@ -38,10 +38,9 @@ const AP_Scheduler::Task Sub::scheduler_tasks[] = {
     SCHED_TASK_CLASS(AP_Baro,             &sub.barometer,    accumulate,          50,  90),
     SCHED_TASK_CLASS(AP_Notify,           &sub.notify,       update,              50,  90),
     SCHED_TASK(one_hz_loop,            1,    100),
-    SCHED_TASK_CLASS(GCS,                 (GCS*)&sub._gcs,   update,             400, 180),
+    SCHED_TASK_CLASS(GCS,                 (GCS*)&sub._gcs,   update_receive,     400, 180),
     SCHED_TASK(gcs_send_heartbeat,     1,    110),
-    SCHED_TASK_CLASS(GCS,                 (GCS*)&sub._gcs,   retry_deferred,      50, 550),
-    SCHED_TASK_CLASS(GCS,                 (GCS*)&sub._gcs,   data_stream_send,    50, 550),
+    SCHED_TASK_CLASS(GCS,                 (GCS*)&sub._gcs,   update_send,         50, 550),
 #if MOUNT == ENABLED
     SCHED_TASK_CLASS(AP_Mount,            &sub.camera_mount, update,              50,  75),
 #endif

ArduSub/GCS_Mavlink.cpp

@@ -1144,9 +1144,8 @@ void Sub::mavlink_delay_cb()
     }
     if (tnow - last_50hz > 20) {
         last_50hz = tnow;
-        gcs().update();
-        gcs().data_stream_send();
-        gcs().retry_deferred();
+        gcs().update_receive();
+        gcs().update_send();
         notify.update();
     }
     if (tnow - last_5s > 5000) {