tests: spi: add nucleo_g431rb to spi_loopback test in async mode

Add nucleo_g431rb to spi_loopback test using spi async configuration.
Such that tests do not only run with syncronous spi configuration
(nucleo_g474re), but also with the asyncronous configuration.

Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>
2 files changed