ALSA: azt3328: fix Kconfig entry

This driver is about as far from being experimental as it can ever get
for an undocumented card, thus create this patch (interestingly it was the only
EXPERIMENTAL remaining in the entire Kconfig file).

Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>