ALSA: make snd_ac97_add_vmaster() static

This patch makes the needlessly global snd_ac97_add_vmaster() static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/ac97/ac97_patch.c

@@ -3381,7 +3381,7 @@ static struct snd_kcontrol *snd_ac97_find_mixer_ctl(struct snd_ac97 *ac97,
 }
 
 /* create a virtual master control and add slaves */
-int snd_ac97_add_vmaster(struct snd_ac97 *ac97, char *name,
+static int snd_ac97_add_vmaster(struct snd_ac97 *ac97, char *name,
 				const unsigned int *tlv, const char **slaves)
 {
 	struct snd_kcontrol *kctl;