ALSA: AACI: simplify codec rate information

There's no need for a specific rule; ALSA's generic AC'97 support
calculates the necessary rate constraint information itself, and
we can use this directly.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>