Merge branch 'drm-st-next-2015-03-19' of git://git.linaro.org/people/benjamin.gaignard/kernel into drm-next

This patch makes STI driver use the atomic helpers.
I have fix the comments done by Daniel on the first version and get
his ack with this second version.
* 'drm-st-next-2015-03-19' of git://git.linaro.org/people/benjamin.gaignard/kernel:
  drm: sti: convert driver to atomic modeset