[fixedwing] allow to trigger kill mode from RC

sw/airborne/firmwares/fixedwing/autopilot_static.c

@@ -123,6 +123,12 @@ void autopilot_static_on_rc_frame(void)
     mode_changed = autopilot_set_mode(RC_LOST_MODE);
   }
 
+#ifdef RADIO_KILL_SWITCH
+  if (imcu_get_radio(RADIO_KILL_SWITCH) < MIN_PPRZ / 2) {
+    autopilot_set_kill_throttle(true);
+  }
+#endif
+
   /* If in-flight, with good GPS but too far, then activate HOME mode
    * In MANUAL with good RC, FBW will allow to override. */
   if (autopilot_get_mode() != AP_MODE_HOME && autopilot_get_mode() != AP_MODE_GPS_OUT_OF_ORDER && autopilot.launch) {