Do not reset terminal state if it is not cleared on resize.

Sponsored by:	The FreeBSD Foundation
It is perfectly possible for keyboard drivers to queue up more than one
key press per notification call. Loop until there are no more queued
key presses, like syscons did. This fixes stuttering observed in particular
on key repeats with ADB and USB keyboards.
Remove some local changes unrelated to r257294.
o Remove extra check for status of processes who hold terminals.
o Clean up and comment things.

Sponsored by:	The FreeBSD Foundation
Add teken_subr_do_resize new method, to update taken sizes w/o reset positions
and use it in case we update terminal size not touching existing data.

Sponsored by:	The FreeBSD Foundation
Define fb newbus interface to connect framebuffer providers with fbd.

Sponsored by:	The FreeBSD Foundation
Allow fbd to be attached as newbus device.

Sponsored by:	The FreeBSD Foundation
o Add fb_getinfo method.
o Attach fbd.
o Comments other possible ways to attach fbd. (Should be moved to man page).

Sponsored by:	The FreeBSD Foundation
Change drm2 to attach fbd as device.
Radeon driver not ready yet.

Sponsored by:	The FreeBSD Foundation
Add link to drmn device.

Sponsored by:	The FreeBSD Foundation
drm: Log error if we fail to attach fbd device
drm/radeon: Implement the FB_GETINFO() newbus callback
Fail to attach if fb_info not passed.

Sponsored by:	The FreeBSD Foundation
Fix copyrights.

Sponsored by:	The FreeBSD Foundation