Fix HDA beep frequency on IDT 92HD73xx and 92HD71Bxx codecs.
These codecs use the standard beep frequency calculation although the
datasheet says it's linear frequency.

Other IDT/STAC codecs might have the same problem.  They should be
fixed individually later.
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>