Fix BABYSTEP_DISPLAY_TOTAL output

Marlin/src/gcode/motion/M290.cpp

           " X", babystep.axis_total[X_AXIS],
           " Y", babystep.axis_total[Y_AXIS],
         #endif
-        " Z", babystep.axis_total[Z_AXIS]
+        " Z", babystep.axis_total[BS_TODO_AXIS(Z_AXIS)]
       );
     }
     #endif