trivial: Don't build the thunderbolt plugins based on udev presence
trivial: Don't build the thunderbolt plugins based on udev presence

GUdev has to exist as a runtime dep, and this check for udev.pc will do nothing
helpful.

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