ALSA: hda - Constify some API function arguments

Also fixed the assignment of multiout.dac_nids to satisfy const.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/patch_sigmatel.c b/sound/pci/hda/patch_sigmatel.c
index 2b590d9..1ce65d4e 100644
--- a/sound/pci/hda/patch_sigmatel.c
+++ b/sound/pci/hda/patch_sigmatel.c
@@ -3072,7 +3072,8 @@
 		printk(KERN_WARNING "stac92xx: No space for DAC 0x%x\n", nid);
 		return 1;
 	} else {
-		spec->multiout.dac_nids[spec->multiout.num_dacs] = nid;
+		snd_BUG_ON(spec->multiout.dac_nids != spec->dac_nids);
+		spec->dac_nids[spec->multiout.num_dacs] = nid;
 		spec->multiout.num_dacs++;
 	}
 	return 0;