ALSA: hdspm - AES32: Enable TCO/Sync-In in snd_hdspm_put_sync_ref()

This patch enables the user to select "TCO" and "Sync In" as a preferred
sync reference on RME AES(32) cards.

Signed-off-by: Adrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>