APMFlightModesComponentController: Remove redundant logic

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

src/AutoPilotPlugins/APM/APMFlightModesComponentController.cc

@@ -68,7 +68,7 @@ void APMFlightModesComponentController::_rcChannelsChanged(int channelCount, int
     for (int i=0; i<6; i++) {
         _rgChannelOptionEnabled[i] = QVariant(false);
         channelValue = pwmValues[i+6];
-        if (channelValue != -1 && channelValue > 1800) {
+        if (channelValue > 1800) {
             _rgChannelOptionEnabled[i] = QVariant(true);
         }
     }