[ALSA] Skip ac97 SPDIF controls

CA0106 driver
Skip building ac97 SPDIF controls via AC97_SCAP_NO_SPDIF.
Clean up the code.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ca0106/ca0106_main.c b/sound/pci/ca0106/ca0106_main.c
index 82533b4..901e42b 100644
--- a/sound/pci/ca0106/ca0106_main.c
+++ b/sound/pci/ca0106/ca0106_main.c
@@ -810,6 +810,7 @@
 
 	memset(&ac97, 0, sizeof(ac97));
 	ac97.private_data = chip;
+	ac97.scaps = AC97_SCAP_NO_SPDIF;
 	return snd_ac97_mixer(pbus, &ac97, &chip->ac97);
 }