ALSA: hda - Don't reset SPDIF in each status change

The SPDIF output is toggled at each time any SPDIF status bits are changed
because of the known problems on some codecs.  But, this also results in
loosing the sync, and the problem is more obvious on HDMI output over
SPDIF.  Since the toggle is necessary only for some codecs, we should
check whether this workaround is needed and skip if unnecessary.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>