Several bug reports suggest that the forcibly resetting IEC958 status
bits is required for AD codecs to get the SPDIF output working
properly after changing streams.

Original fix credit to Javeed Shaikh.

BugLink: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/359361Reported-by: NRobin Kreis <r.kreis@uni-bremen.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>