No functional change, just code factoring to have the Python bindings in
one location, and all the ports use those same bindings.
Signed-off-by: Damien George <damien@micropython.org>
Rework the ADC implementation to follow the improved ADC/ADCBlock API.
This adds support for calibrated voltage readings and the ADC2 block. The
ADC API is backwards compatible with what it was before this change.
Resolves#6219.