remove analog_imu_init, use general imu_init

sw/airborne/firmwares/fixedwing/main_ap.c

@@ -499,7 +499,7 @@ void init_ap( void ) {
 #endif
 
 #ifdef USE_ANALOG_IMU
-  analog_imu_init();
+  imu_init();
 #endif
 
   /************* Links initialization ***************/

sw/airborne/subsystems/ahrs/dcm/analogimu.c

@@ -57,10 +57,6 @@ float imu_pitch_neutral = RadOfDeg(IMU_PITCH_NEUTRAL_DEFAULT);
 
 #if ! (defined SITL || defined HITL)
 
-void analog_imu_init( void ) {
-  imu_impl_init();
-}
-
 void analog_imu_offset_set( void ) {
   // read IMU, really?
   imu_periodic();

sw/airborne/subsystems/ahrs/dcm/analogimu.h

@@ -35,8 +35,6 @@
 extern float imu_roll_neutral;
 extern float imu_pitch_neutral;
 
-//functions
-void analog_imu_init( void );
 void analog_imu_downlink( void );
 void estimator_update_state_analog_imu( void );
 void analog_imu_offset_set( void );