Merge tag 'drm-intel-fixes-2015-10-01' of git://anongit.freedesktop.org/drm-intel...

a few i915 fixes for v4.3.

* tag 'drm-intel-fixes-2015-10-01' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Call non-locking version of drm_kms_helper_poll_enable(), v2
  drm: Add a non-locking version of drm_kms_helper_poll_enable(), v2
  drm/i915: Consider HW CSB write pointer before resetting the sw read pointer
  drm/i915/skl: Don't call intel_prepare_ddi when encoder list isn't yet initialized.