(APM Sub) Fix fence alt parameter in safety page

src/AutoPilotPlugins/APM/APMSafetyComponentSub.qml

@@ -42,7 +42,7 @@ SetupPage {
             property Fact _failsafeTempValue:      controller.getParameterFact(-1, "FS_TEMP_MAX")
 
             property Fact _fenceAction: controller.getParameterFact(-1, "FENCE_ACTION")
-            property Fact _fenceAltMax: controller.getParameterFact(-1, "FENCE_ALT_MAX")
+            property Fact _fenceAltMax: controller.getParameterFact(-1, "r.FENCE_ALT_MIN")
             property Fact _fenceEnable: controller.getParameterFact(-1, "FENCE_ENABLE")
             property Fact _fenceMargin: controller.getParameterFact(-1, "FENCE_MARGIN")
             property Fact _fenceType:   controller.getParameterFact(-1, "FENCE_TYPE")

src/FirmwarePlugin/APM/ArduSubFirmwarePlugin.cc

@@ -62,6 +62,8 @@ ArduSubFirmwarePlugin::ArduSubFirmwarePlugin(void)
         remapV3_5["SERVO13_FUNCTION"] = QStringLiteral("RC13_FUNCTION");
         remapV3_5["SERVO14_FUNCTION"] = QStringLiteral("RC14_FUNCTION");
 
+        remapV3_5["FENCE_ALT_MIN"] = QStringLiteral("FENCE_DEPTH_MAX");
+
         _remapParamNameIntialized = true;
     }
 }