Flysky Hall Stick MOD using UART4 by disabling stick A/D, resolving #140. (#149)

* Flysky Hall Stick MOD using UART4 by disabling stick A/D.

* Fixed build error.

* Added Flysky hall stick mod in test targets.

* Changed ADC disable for Flysky hall sticks method.

radio/src/opentx.cpp

@@ -32,6 +32,8 @@
 #include "audio_driver.h"
 #endif
 
+extern uint16_t get_flysky_hall_adc_value(uint8_t ch);
+
 RadioData  g_eeGeneral;
 ModelData  g_model;
 
@@ -1102,7 +1104,7 @@ void getADC()
 
 #if defined(FLYSKY_HALL_STICKS)
     if (x < 4)
-      v = get_hall_adc_value(x) >> (1 - ANALOG_SCALE);
+      v = get_flysky_hall_adc_value(x) >> (1 - ANALOG_SCALE);
     else
       v = getAnalogValue(x) >> (1 - ANALOG_SCALE);
 #else