The bit-bang implementation was replaced with the RMT implementation in
599b61c08687ca077e3b0e115d5b76affcc673ca. This commit brings back that
bit-bang code, and allows it to be selected via the new static method:
esp32.RMT.bitstream_channel(None)
The bit-bang implementation may be useful if the RMT needs to be used for
something else, or if bit-banging is more stable in certain applications.
Signed-off-by: Damien George <damien@micropython.org>
a3bbd5332b