ekf2: add dedicated EKF2_CONFIG_TERRAIN in kconfig

- new estimator_aid_src_terrain_range_finder for HAGL RNG

src/modules/ekf2/EKF/mag_control.cpp

@@ -123,17 +123,17 @@ void Ekf::controlMagFusion()
 
 bool Ekf::checkHaglYawResetReq() const
 {
+#if defined(CONFIG_EKF2_TERRAIN)
 	// We need to reset the yaw angle after climbing away from the ground to enable
 	// recovery from ground level magnetic interference.
 	if (_control_status.flags.in_air && _control_status.flags.yaw_align && !_control_status.flags.mag_aligned_in_flight) {
 		// Check if height has increased sufficiently to be away from ground magnetic anomalies
 		// and request a yaw reset if not already requested.
-#if defined(CONFIG_EKF2_RANGE_FINDER)
 		static constexpr float mag_anomalies_max_hagl = 1.5f;
 		const bool above_mag_anomalies = (getTerrainVPos() - _state.pos(2)) > mag_anomalies_max_hagl;
 		return above_mag_anomalies;
-#endif // CONFIG_EKF2_RANGE_FINDER
 	}
+#endif // CONFIG_EKF2_TERRAIN
 
 	return false;
 }