Blimp: remove unused Log_Write_Precland method

... and a dead define to match

Blimp/Blimp.h

@@ -431,7 +431,6 @@ private:
     void Log_Write_Data(LogDataID id, float value);
     void Log_Write_Parameter_Tuning(uint8_t param, float tuning_val, float tune_min, float tune_max);
     void Log_Sensor_Health();
-    void Log_Write_Precland();
     void Log_Write_GuidedTarget(uint8_t target_type, const Vector3f& pos_target, const Vector3f& vel_target);
     void Log_Write_SysID_Setup(uint8_t systemID_axis, float waveform_magnitude, float frequency_start, float frequency_stop, float time_fade_in, float time_const_freq, float time_record, float time_fade_out);
     void Log_Write_SysID_Data(float waveform_time, float waveform_sample, float waveform_freq, float angle_x, float angle_y, float angle_z, float accel_x, float accel_y, float accel_z);

Blimp/Log.cpp

@@ -464,7 +464,6 @@ void Blimp::Log_Write_Data(LogDataID id, uint16_t value) {}
 void Blimp::Log_Write_Data(LogDataID id, float value) {}
 void Blimp::Log_Write_Parameter_Tuning(uint8_t param, float tuning_val, float tune_min, float tune_max) {}
 void Blimp::Log_Sensor_Health() {}
-void Blimp::Log_Write_Precland() {}
 void Blimp::Log_Write_GuidedTarget(uint8_t target_type, const Vector3f& pos_target, const Vector3f& vel_target) {}
 void Blimp::Log_Write_SysID_Setup(uint8_t systemID_axis, float waveform_magnitude, float frequency_start, float frequency_stop, float time_fade_in, float time_const_freq, float time_record, float time_fade_out) {}
 void Blimp::Log_Write_SysID_Data(float waveform_time, float waveform_sample, float waveform_freq, float angle_x, float angle_y, float angle_z, float accel_x, float accel_y, float accel_z) {}

Blimp/defines.h

@@ -139,7 +139,6 @@ enum LoggingParameters {
     LOG_MOTBATT_MSG,
     LOG_PARAMTUNE_MSG,
     LOG_HELI_MSG,
-    LOG_PRECLAND_MSG,
     LOG_GUIDEDTARGET_MSG,
     LOG_SYSIDD_MSG,
     LOG_SYSIDS_MSG,