ALSA: hda: fix kstrdup return value

In kstrdup we should return -ENOMEM when it reports an
memory allocation failure, while the -ENODEV is referred
to a failure in finding the cpu node in the device tree.

Signed-off-by: Heloise NH <kernelpatch_update@163.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>