dell: Fix a trivial warning spotted by clang
dell: Fix a trivial warning spotted by clang

vathpela/fwupd,superm1/fwupd,fwupd/fwupd,hughsie/fwupd,hughsie/fwupd,superm1/fwupd,fwupd/fwupd,vathpela/fwupd,superm1/fwupd,fwupd/fwupd,fwupd/fwupd,hughsie/fwupd,hughsie/fwupd,vathpela/fwupd,vathpela/fwupd