drm/i915: Update to Linux 3.11

drm/i915: Update to Linux 3.11

* Valleyview/Baytrail support improvements. Baytrail support is
  no longer considered experimental.

* VECS engine support on Haswell. The Video Enhancement Command
  Streamer is used by libva for some post-processing tasks.

* Power management improvements, especially on Haswell.

* Hotplug improvements.

* Output and modeset improvements. Using 30bpp modes is now possible.

* Various bugfixes and Stability improvements, including memory
  corruption and GPU hang fixes after a suspend/resume sequence.

v2: i915_irq.c lock ordering fix, reported by zrj@

v3: backlight spinlock fixes from Romick