drm/i915/sdvo: Port the infoframe code to the shared infrastructure

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>