I've forgotten to sync the documentation with the actually available
options for some time.  Now all updated.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

A simple reformat with the description list of ReST, and the content
was kept as is, but renamed as Documentation/sound/hd-audio/models.rst.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>