SPRacingF3Mini - First cut of transponder system.

Implementation is DMA buffer based, just like the WS2811 LED Strip code,
so that there is minimal impact on flight performance.

Currently the code is mutually exclusive with the LED_STRIP code and
there is no means to set the transponder code.

src/main/mw.c

@@ -64,6 +64,8 @@
 #include "io/serial_msp.h"
 #include "io/statusindicator.h"
 #include "io/asyncfatfs/asyncfatfs.h"
+#include "io/transponder_ir.h"
+
 
 #include "rx/rx.h"
 #include "rx/msp.h"
@@ -754,6 +756,10 @@ void taskMainPidLoop(void)
         handleBlackbox();
     }
 #endif
+
+#ifdef TRANSPONDER
+    updateTransponder();
+#endif
 }
 
 // Function for loop trigger