ALSA: hda - Keep char arrays in input_mux items

Keep char array in the input_mux item itself instead of pointing to
an external string.  This is a preliminary work for improving the
input-mux name based on the pin role.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_local.h b/sound/pci/hda/hda_local.h
index fb56174..b448b0a 100644
--- a/sound/pci/hda/hda_local.h
+++ b/sound/pci/hda/hda_local.h
@@ -215,7 +215,7 @@
  */
 #define HDA_MAX_NUM_INPUTS	16
 struct hda_input_mux_item {
-	const char *label;
+	char label[32];
 	unsigned int index;
 };
 struct hda_input_mux {
@@ -391,8 +391,8 @@
 };
 
 struct auto_pin_cfg;
-const char *snd_hda_get_input_pin_label(const struct auto_pin_cfg *cfg,
-					int input);
+void snd_hda_get_input_pin_label(const struct auto_pin_cfg *cfg,
+				 int input, char *label);
 
 struct auto_pin_cfg {
 	int line_outs;