logx, logy not applying when datashade=True

When `logx` or `logy` is set it doesn't log the points positions if `datashade=True`, it just changes the scale on the axis. Here's an example for `logx`:

```python
import pandas as pd
import numpy as np
import holoviews as hv

d = pd.DataFrame({
"x": np.linspace(1, 100, 10000) + np.random.rand(10000),
"y": np.linspace(1, 100, 10000) + np.random.rand(10000)
})

( d.hvplot.scatter("x", "y", logx=True)
+ d.hvplot.scatter("x", "y", logx=True, datashade=True)).cols(1)
```