This patch conditions AC97 control creation by whether or not the
codec is an AD18xx codec. This fixes the case where the default control
would get created and then snd_ac97_mixer_build fails out when creation
of ad18xx specific control would get attempted. This problem was found
and debuged by Marcelo Tosatti.
Signed-off-by: NJaya Kumar <jayakumar.alsa@gmail.com>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>