Resurrecting fbdev

It stalled for a few years, but a few folks from rh and suse have picked up the pieces again. We have simpledrm now merged, which means firmware fbdev drivers (efifb, vesafb, ...) aren't needed anymore, and you can have a pure kms world.

Next step is to get some kernel console on top of drm landed, for (emergency) logging. This should probably wait for the remaining console_lock rework so that we don't have to maintain our own kthread for offloading.

At that point all the pieces are in places for distros to ditch CONFIG_VT and fbcon and use kmscon for non-graphical shell logins on the local machine. Apparently logind/seatd already can do all the vt switching without CONFIG_VT (since that's needed for all the additional seats anyway), so that part is covered.

It might all actually happen this decade!