Update to the test added in 1e98c4cb75,
changes the SPI pins for ESP32-C3 (IO 18 and 19 are the native USB pins).
Signed-off-by: Angus Gratton <angus@redyak.com.au>
Based on machine_i2s_rate, allows testing basic SPI functionality and
timings.
Implemented and confirmed working for rp2, esp32, and pyboard.
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
