It was only used for prime import, which is now handled by
drm_prime.c.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Qiang Yu <yuq825@gmail.com>
Cc: lima@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20190614203615.12639-44-daniel.vetter@ffwll.ch