crashes when autoScaleMinMaxEnabled == true and no entry in visibleRange

It happens when I do like this
1. `autoScaleMinMaxEnabled = true` and `axisMinimum = 0`;
```
_chartView.xAxis.axisMinimum = 0;
_chartView.autoScaleMinMaxEnabled = true;
```
2. drag/zoom enabled
3. drag the chart til visibleXRange is 0~29

I believe that the YAxis gets NaN range because there is no entries for calculating.
Now I have to check the data when chart range changed, and set a good range to it, to keep chart displaying with no data and with no crash.

If you have any idea to check or set the YAxis range to make sure it won't get crashed?