Adjust the sensor firmware paths for hexagonrpcd 0.3.1.
Also drop board-2.bin file which is now upstream and use upstream mba.mbn
and wlanmdsp.mbn.
[ci:skip-build]: already built successfully in CI
Provide common board-2.bin file, extended from linux-firmware.
This file will be temporarily provided and dropped once all devices
are added to upstream linux-firmware's board-2.bin file.