ALSA: ac97_patch make functions static

Only used in ac97_codec by including ac97_patch.c directly, effectively static

Found by sparse:
sound/pci/ac97/ac97_patch.c:3551:5: warning: symbol 'patch_vt1617a' was not declared. Should it be static?
sound/pci/ac97/ac97_patch.c:3767:5: warning: symbol 'patch_vt1618' was not declared. Should it be static?
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>

sound/pci/ac97/ac97_patch.c

@@ -3548,7 +3548,7 @@ static const struct snd_kcontrol_new snd_ac97_controls_vt1617a[] = {
 	},
 };
 
-int patch_vt1617a(struct snd_ac97 * ac97)
+static int patch_vt1617a(struct snd_ac97 * ac97)
 {
 	int err = 0;
 	int val;
@@ -3764,7 +3764,7 @@ static const struct snd_kcontrol_new snd_ac97_controls_vt1618[] = {
 	}
 };
 
-int patch_vt1618(struct snd_ac97 *ac97)
+static int patch_vt1618(struct snd_ac97 *ac97)
 {
 	return patch_build_controls(ac97, snd_ac97_controls_vt1618,
 				    ARRAY_SIZE(snd_ac97_controls_vt1618));