ALSA: intel8x0: Add clock quirk entry for AD1981B on IBM ThinkPad X41.

The clock measurement on the AC'97 audio card found in the IBM ThinkPad X41
will often fail, so add a quirk entry to fix it.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=441087
Cc: <stable@vger.kernel.org>
Signed-off-by: Vittorio Gambaletta <linuxbugs@vittgam.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>