wacom-usb: Fix firmware parse regression from FuFirmwareImage removal
wacom-usb: Fix firmware parse regression from FuFirmwareImage removal

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