drm/i915/gtt: Tear down setup and cleanup macros for page dma

We don't use common codepaths to setup and cleanup page
directories vs page tables. So their setup and cleanup macros
are of no use and can be removed.

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190705215204.4559-2-chris@chris-wilson.co.uk