Move frame-buffer back to subpackage, patch bugs
More fun related to #1518464. This should fix everything really
hard! We backport a patch that should actually fix #1518464 if
frame-buffer is present but drm is not...but we also backport a
patch that fixes boot with 'rhgb' when neither renderer is
present, and move frame-buffer back to the subpackage, as we
think that's the 'most correct' package layout assuming no bugs.