trivial: Do not call setup() vfuncs when we're never calling coldplug
trivial: Do not call setup() vfuncs when we're never calling coldplug

Now all plugins define custom GTypes in the _init() vfunc, and so
there's no need to actually probe devices to just get access to those.

This means you can get results from `fwupdtool get-firmware-types`
about two orders of magnitude quicker.

fwupd/fwupd,fwupd/fwupd,fwupd/fwupd,fwupd/fwupd