Copter: use resetHeightDatum() and getLastYawResetAngle()

ArduCopter/Attitude.cpp

@@ -53,7 +53,7 @@ float Copter::get_pilot_desired_yaw_rate(int16_t stick_angle)
 void Copter::check_ekf_yaw_reset()
 {
     float yaw_angle_change_rad = 0.0f;
-    if (ahrs.get_NavEKF().getLastYawResetAngle(yaw_angle_change_rad)) {
+    if (ahrs.getLastYawResetAngle(yaw_angle_change_rad)) {
         attitude_control.shift_ef_yaw_target(ToDeg(yaw_angle_change_rad) * 100.0f);
     }
 }

ArduCopter/motors.cpp

@@ -165,7 +165,7 @@ bool Copter::init_arm_motors(bool arming_from_gcs)
 
     if (ap.home_state == HOME_UNSET) {
         // Reset EKF altitude if home hasn't been set yet (we use EKF altitude as substitute for alt above home)
-        ahrs.get_NavEKF().resetHeightDatum();
+        ahrs.resetHeightDatum();
         Log_Write_Event(DATA_EKF_ALT_RESET);
     } else if (ap.home_state == HOME_SET_NOT_LOCKED) {
         // Reset home position if it has already been set before (but not locked)