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/patch_via.c b/sound/pci/hda/patch_via.c
index b94cdee..de4839e 100644
--- a/sound/pci/hda/patch_via.c
+++ b/sound/pci/hda/patch_via.c
@@ -458,9 +458,7 @@
 	if (!knew->name)
 		return -ENOMEM;
 	if (get_amp_nid_(val))
-		knew->subdevice = HDA_SUBDEV_NID_FLAG |
-				  HDA_SUBDEV_AMP_FLAG |
-				  get_amp_nid_(val);
+		knew->subdevice = HDA_SUBDEV_AMP_FLAG;
 	knew->private_value = val;
 	return 0;
 }