Pull drm mst fixes from Daniel Vetter:
"Special pull request for mst fixes since most of the patches touch
code outside of i915 proper. DRM parts have also been reviewed by
Thierry (nvidia) since Dave's enjoying vacations"
* tag 'topic/mst-fixes-2015-08-04' of git://anongit.freedesktop.org/drm-intel:
drm/atomic-helpers: Make encoder picking more robust
drm/dp-mst: Remove debug WARN_ON
drm/i915: Fixup dp mst encoder selection
drm/atomic-helper: Add an atomice best_encoder callback