drm/i915/hdmi: send AVI info frames on ILK+ as well

On Ironlake and above, we have per-transcoder DIP registers, so use them
for sending DIPs like AVI infoframes on ILK and above.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>