And a way to pack hdmi_infoframe generically.

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Acked-by: NDave Airlie <airlied@gmail.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add generic helpers to pack HDMI infoframes into binary buffers.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>