Just enough to make the code not barf...

Init BDW display to look like HSW. For the simulator this should be
fine, but this will probably require more work.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: Add a FIXME comment about RCS flips being untested on bdw.
Also add a note that hblank events are reserved on bdw+ in DERRMR.]
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>