trivial: amt: correct a potential lack of error
trivial: amt: correct a potential lack of error

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