Don't choke on unknown elements when we do know how to skip them.
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452518948-16469-1-git-send-email-jani.nikula@intel.com