drm/i915: Convert intel_dp to use atomic state

Slightly less straightforward. Some of the drrs calls are done from
workers or from intel_ddi.c, pass along crtc_state when we can,
or crtc->config when we can't.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470755054-32699-15-git-send-email-maarten.lankhorst@linux.intel.com


Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>