HDMI 4k support

[Damien Lespiau <damien.lespiau@intel.com>]

This series parses one of the dark corners of the EDID to expose "4k x 2k"
modes to userspace. Those modes are part of HDMI 1.4.

To complete the 4k HDMI support, one needs:

  * Hardware able to output a 300 MHz TMDS clock (Haswell can do that) and
    Daniel's patch to bump that limit in the kernel (already queued).

      Author: Daniel Vetter <daniel.vetter@ffwll.ch>
      Date:   Mon Jul 22 18:02:39 2013 +0200

          drm/i915: fix hdmi portclock limits

  * The 2 patches attached here to parse the HDMI VICs in the HDMI vendor
    specific CEA block.

  * A DDX patch (for UXA) already merged (and in 2.21.14)

      Author: Damien Lespiau <damien.lespiau@intel.com>
      Date:   Wed Jul 31 18:50:51 2013 +0100

          uxa/display: Keep the EDID blob around for the lifetime of an output

  * My "Use the TMDS maximum frequency to check mode dot clock" xserver series:

    http://lists.x.org/archives/xorg-devel/2013-August/037297.html

The bug referencing all that and the testing by QA:

  https://bugs.freedesktop.org/show_bug.cgi?id=67030
    
Additionally, edid-decode has been taught about those modes as well:

  http://lists.freedesktop.org/archives/dri-devel/2013-August/043078.html

-- 
Damien