Remove former dummy/ files which now have an actual implementation
in common/ .
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D38269
All those are needed for drm-kmod.
Add them to base in another directory that will be append in the CFLAGS.
Reviewed by: bz
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D36110