This patch adds a QTest for NPCM7XX SMBus's single byte mode. It sends a
byte to a device in the evaluation board, and verify the retrieved value
is equivalent to the sent value.

Reviewed-by: Doug <Evans&lt;dje@google.com>
Reviewed-by: Tyrong <Ting&lt;kfting@nuvoton.com>
Signed-off-by: Hao Wu <wuhaotsh@google.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20210210220426.3577804-5-wuhaotsh@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>