As most other board Miix uses board-id = 0xff, so define calibration
variant to distinguish it from other devices with the same chip_id.
qmi chip_id 0x30214 chip_family 0x4001 board_id 0xff soc_id 0x40010002
Cc: Kalle Valo <kvalo@xxxxxxxxxx>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>