[air_data] use static function for telemetry

sw/airborne/subsystems/air_data.c

@@ -30,7 +30,6 @@
 
 #include "subsystems/air_data.h"
 #include "subsystems/abi.h"
-#include "subsystems/datalink/telemetry.h"
 
 /** global AirData state
  */
@@ -47,15 +46,23 @@ static void pressure_abs_cb(uint8_t __attribute__((unused)) sender_id, const flo
   air_data.pressure = *pressure;
 }
 
+#if DOWNLINK
+#include "subsystems/datalink/telemetry.h"
+
+static void send_baro_raw(void) {
+  DOWNLINK_SEND_BARO_RAW(DefaultChannel, DefaultDevice,
+                         &air_data.pressure, &air_data.differential);
+}
+#endif
+
 /** AirData initialization. Called at startup.
  *  Bind ABI messages
  */
 void air_data_init( void ) {
   AbiBindMsgBARO_ABS(AIR_DATA_BARO_ABS_ID, &pressure_abs_ev, pressure_abs_cb);
+
+#if DOWNLINK
   register_periodic_telemetry(DefaultPeriodic, "BARO_RAW", send_baro_raw);
+#endif
 }
 
-void send_baro_raw(void) {
-  DOWNLINK_SEND_BARO_RAW(DefaultChannel, DefaultDevice,
-                         &air_data.pressure, &air_data.differential);
-}

sw/airborne/subsystems/air_data.h

@@ -52,7 +52,5 @@ extern struct AirData air_data;
  */
 extern void air_data_init( void );
 
-extern void send_baro_raw(void);
-
 #endif /* AIR_DATA_H */