This particular laptop has its motherboard replaced and after that, even
with the latest BIOS, some DMI identification strings have become
"INVALID". This includes DMI_PRODUCT_VERSION which results Wifi being
blocked.

It seems that DMI_BOARD_NAME is still valid so use that as an
alternative for Lenovo Yoga 900.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>