drm/i915/sdvo: Include YRPB as an additional TV output type

Reported-and-tested-by: Bo Wang &lt; <bo.b.wang@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36997


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>