PDM mic buffer size causes hard reset and boot into safemode

[AidenRay]

Running the following code from readthedocs causes a hard reset, and the CPX to run in safemode (not always).

import board

# Prep a buffer to record into
b = bytearray(200)
with audiobusio.PDMIn(board.MICROPHONE_CLOCK, board.MICROPHONE_DATA) as mic:
    mic.record(b, len(b)) ```

Increasing the buffer size to 8000 ('b = bytearray(8000)') fixes the issue.

[AidenRay]

I tested a bunch of buffer sizes.

A length of 1504 is fine, whereas a length of 2963 hard resets.
So simply increasing the buffer length doesn't seem to solve it.

[dhalbert]

Fixed by #479.