[ALSA] hda-codec - Fix a typo

The AMP mute bit is bit 7.  No real influence since no one uses this
definition yet, though...
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>

sound/pci/hda/hda_codec.h

@@ -233,7 +233,7 @@ enum {
  */
 
 /* Amp gain/mute */
-#define AC_AMP_MUTE			(1<<8)
+#define AC_AMP_MUTE			(1<<7)
 #define AC_AMP_GAIN			(0x7f)
 #define AC_AMP_GET_INDEX		(0xf<<0)