usb-device-cdc raises TypeError when using default timeout of None and going to block

https://.com/micropython/micropython-lib/blob/master/micropython/usb/usb-device-cdc/usb/device/cdc.py#L368
and same for read function.

```python
            # check for timeout
            if time.ticks_diff(time.ticks_ms(), start) >= self._timeout:
                return len(buf) - len(mv)

            machine.idle()
```
should be something like this:
```python
            if isinstance(self._timeout, int) and time.ticks_diff(time.ticks_ms(), start) >= self._timeout:


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