Fix simple mode logic

src/AutoPilotPlugins/PX4/PX4FlightModes.qml

@@ -41,9 +41,10 @@ QGCView {
     viewPanel:  panel
 
     property Fact _nullFact
-    property Fact _rcMapFltmode:    controller.parameterExists(-1, "RC_MAP_FLTMODE") ? controller.getParameterFact(-1, "RC_MAP_FLTMODE") : _nullFact
-    property Fact _rcMapModeSw:     controller.getParameterFact(-1, "RC_MAP_MODE_SW")
-    property bool _simpleMode:      controller.parameterExists(-1, "RC_MAP_FLTMODE") && _rcMapFltmode.value > 0
+    property bool _rcMapFltmodeExists:  controller.parameterExists(-1, "RC_MAP_FLTMODE")
+    property Fact _rcMapFltmode:        _rcMapFltmodeExists ? controller.getParameterFact(-1, "RC_MAP_FLTMODE") : _nullFact
+    property Fact _rcMapModeSw:         controller.getParameterFact(-1, "RC_MAP_MODE_SW")
+    property bool _simpleMode:          _rcMapFltmodeExists ? _rcMapFltmode.value > 0 || _rcMapModeSw.value == 0 : false
 
     QGCPalette { id: qgcPal; colorGroupEnabled: panel.enabled }