drm/i915: add some registers need for displayport MST support.
drm/i915: add some registers need for displayport MST support.

These are just from the Haswell spec.

Reviewed-by: Todd Previte <7c35167087125e218d92ade7e6519b3dfc3b9d1a@gmail.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs