wacom-usb: Legacy Bluetooth module reports version numbers in little-endian
wacom-usb: Legacy Bluetooth module reports version numbers in little-endian

While the modern firmware interfaces report their version numbers in
big-endian form, reading the legacy Bluetooth module version via the
FU_WAC_REPORT_ID_GET_FIRMWARE_VERSION_BLUETOOTH report requires us to
actually parse a little-endian value. This difference was overlooked
when making changes to the version parsing code in commit 50a4ec70e6a8.
This commit restores the proper interpretation.

Fixes: 50a4ec70e6a8 (wacom_usb: Firmware versions are packed BCD, not "decimal")

fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,hughsie/fwupd