The legacy I2S "shim" is removed and replaced by the new I2S driver. The
new driver fixes a bug where mono audio plays only in one channel.
Application code size is reduced by 2672 bytes with this change. Tested on
ESP32, ESP32+spiram, ESP32-S3 using example code from
https://github.com/miketeachman/micropython-i2s-examples
Signed-off-by: Mike Teachman <mike.teachman@gmail.com>