AP_NavEKF3: correct compilation in SITL when logging is disabled

this code is gated on HAL_BOARD_SITL already, and usually we have logging in SITL.  But not always

libraries/AP_NavEKF3/AP_NavEKF3_core.cpp

@@ -2147,6 +2147,7 @@ void NavEKF3_core::bestRotationOrder(rotationOrder &order)
 // and log with value generated by NavEKF3_core::calcTiltErrorVariance()
 void NavEKF3_core::verifyTiltErrorVariance()
 {
+#if HAL_LOGGING_ENABLED
     const Vector3f gravity_ef = Vector3f(0.0f,0.0f,1.0f);
     Matrix3f Tnb;
     const float quat_delta = 0.001f;
@@ -2186,6 +2187,7 @@ void NavEKF3_core::verifyTiltErrorVariance()
         };
         AP::logger().WriteBlock(&msg, sizeof(msg));
     }
+#endif  // HAL_LOGGING_ENABLED
 }
 #endif