ALSA: hda - do not add non-existing Mic boost controls

If the input node does not have any volume capable input amp,
don't add such a control.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
index c33e019..05dfeb7 100644
--- a/sound/pci/hda/hda_generic.c
+++ b/sound/pci/hda/hda_generic.c
@@ -2826,6 +2826,9 @@
 			struct nid_path *path;
 			unsigned int val;
 
+			if (!nid_has_volume(codec, nid, HDA_INPUT))
+				continue;
+
 			label = hda_get_autocfg_input_label(codec, cfg, i);
 			if (prev_label && !strcmp(label, prev_label))
 				type_idx++;