drm: Apply range restriction after color adjustment when allocation

mm->color_adjust() compares the hole with its neighbouring nodes. They
only abutt before we restrict the hole, so we have to apply color_adjust
before we apply the range restriction.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-36-chris@chris-wilson.co.uk