drm/mm: Do DRM_MM_CREATE_TOP adj_start calculation after color_adjust

The adj_start calculation for DRM_MM_CREATE_TOP should happen after
mm->color_adjust. There was an inconsistency between
drm_mm_insert_helper_range
and drm_mm_insert_helper, as the later was already updating after
color_adjust.

Didn't spot it before, as color_adjust is only done in systems without
LLC. But I'm not aware of anybody using this test case yet.

Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>