drm/i915/chv: Add DDL register defines for Cherryview

Fill in the sprite bits for DDL1/DDL2 registers, and add DDL3.

Still need to write the code to use these...

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>