AD1986A has a hardware problem that it cannot share a stream with
multiple pins properly.  The problem occurs e.g. when a volume is changed
during playback.
So far, hda-intel driver unconditionally assigns the stream to multiple
output pins in copy-front mode, and this should be avoided for AD1986A
codec.
The original fix patch was by zhejiang <zhe.jiang@intel.com>.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>