ALSA: hda - simplify usage of HDA_SUBDEV_AMP_FLAG

The HDA_SUBDEV_NID_FLAG is duplicate for amplifier control elements. Move
get_amp_nid_() call to the snd_hda_ctl_add() function.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index c9af15e..c848ec0 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1733,11 +1733,14 @@
 	unsigned short flags = 0;
 	struct hda_nid_item *item;
 
-	if (kctl->id.subdevice & HDA_SUBDEV_AMP_FLAG)
+	if (kctl->id.subdevice & HDA_SUBDEV_AMP_FLAG) {
 		flags |= HDA_NID_ITEM_AMP;
+		if (nid == 0)
+			nid = get_amp_nid_(kctl->private_value);
+	}
 	if ((kctl->id.subdevice & HDA_SUBDEV_NID_FLAG) != 0 && nid == 0)
 		nid = kctl->id.subdevice & 0xffff;
-	if (kctl->id.subdevice & 0xf0000000)
+	if (kctl->id.subdevice & (HDA_SUBDEV_NID_FLAG|HDA_SUBDEV_AMP_FLAG))
 		kctl->id.subdevice = 0;
 	err = snd_ctl_add(codec->bus->card, kctl);
 	if (err < 0)