Document everything that was introduced after version 155, which seems
to be the baseline for some of the later documentation. No functional
changes.

Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/11e8200e750eea13604b2d21e56b37cd5e6d9ab0.1503600621.git.jani.nikula@intel.com