ALSA: hda - Fix regression for slave SPDIF setups

The commit [a551d914: ALSA: hda - Use regmap for command verb
caches, too] introduced a regression due to a typo in the conversion;
the IEC958 status bits of slave digital devices aren't updated
correctly.  This patch corrects it.

Fixes: a551d914 ('ALSA: hda - Use regmap for command verb caches, too')
Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>