ALSA: emu10k1: don't create regular S/PDIF controls for E-MU cards

These ports are unused on these cards.

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230510173722.3072439-1-oswald.buddenhagen@gmx.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>