ALSA: hda - Fix NID association for capture mixers

Fix the wrong implementation of NID <-> kctl mapping for capture mixers
introduced by the ocmmit 5b0cb1d850c26893b1468b3a519433a1b7a176be.
So far, the driver returns an error at probe.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index e7cdc6a..a451990 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -2551,8 +2551,7 @@
 		hda_nid_t *nids = spec->capsrc_nids;
 		if (!nids)
 			nids = spec->adc_nids;
-		err = snd_hda_add_nids(codec, kctl, i, nids,
-				       spec->input_mux->num_items);
+		err = snd_hda_add_nid(codec, kctl, i, nids[i]);
 		if (err < 0)
 			return err;
 	}