remove optlow dependency

app.py

@@ -91,7 +91,7 @@ BUILD_OPTIONS = [
     Feature('MSP', 'MSP_COMPASS', 'HAL_MSP_COMPASS_ENABLED', 'Enable MSP Compass', 0, 'MSP,OSD'),
     Feature('MSP', 'MSP_BARO', 'HAL_MSP_BARO_ENABLED', 'Enable MSP Baro', 0, 'MSP,OSD'),
     Feature('MSP', 'MSP_AIRSPEED', 'HAL_MSP_AIRSPEED_ENABLED', 'Enable MSP AirSpeed', 0, 'MSP,OSD'),
-    Feature('MSP', 'MSP_OPTICALFLOW', 'HAL_MSP_OPTICALFLOW_ENABLED', 'Enable MSP OpticalFlow', 0, 'MSP,OSD,OPTFLOW'),
+    Feature('MSP', 'MSP_OPTICALFLOW', 'HAL_MSP_OPTICALFLOW_ENABLED', 'Enable MSP OpticalFlow', 0, 'MSP,OSD'), # also OPTFLOW dep
     Feature('MSP', 'MSP_RANGEFINDER', 'HAL_MSP_RANGEFINDER_ENABLED', 'Enable MSP Rangefinder', 0, 'MSP,OSD'),
     Feature('MSP', 'MSP_DISPLAYPORT', 'HAL_WITH_MSP_DISPLAYPORT', 'Enable MSP DisplayPort OSD (aka CANVAS MODE)', 0, 'MSP,OSD'),