[Intel-gfx] [RFC v3] refactor intel display a bit more

[Dave Airlie]

The first 4 patches are fixed up and reviewed, so it would be
good if we could land those at least.

I haven't had much time to rework the others, I've removed the legacy,
and added header files and renamed some functions where it wasn't too
intrusive.

I think the file names probably do need revisiting, for the later
patches and the hsw fdi patch is still a bit rough IMO.

I'm away for a week now, so I'll see what I can revisit when I return
or feel free to munge these in the meantime into whatever works.

Dave.