ASoC: Remove unused snd_soc_info_volsw_ext()

The SOC_SINGLE_EXT control has been using snd_soc_info_volsw() for its info
callback since commit 1c433fbd ("[ALSA] soc - 0.13 ASoC headers"). The
snd_soc_info_volsw_ext() function has been unused ever since then, so remove it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

include/sound/soc.h

@@ -497,8 +497,6 @@ int snd_soc_put_value_enum_double(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol);
 int snd_soc_info_volsw(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_info *uinfo);
-int snd_soc_info_volsw_ext(struct snd_kcontrol *kcontrol,
-	struct snd_ctl_elem_info *uinfo);
 #define snd_soc_info_bool_ext		snd_ctl_boolean_mono_info
 int snd_soc_get_volsw(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol);

sound/soc/soc-core.c

@@ -2577,32 +2577,6 @@ int snd_soc_info_enum_ext(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_GPL(snd_soc_info_enum_ext);
 
-/**
- * snd_soc_info_volsw_ext - external single mixer info callback
- * @kcontrol: mixer control
- * @uinfo: control element information
- *
- * Callback to provide information about a single external mixer control.
- *
- * Returns 0 for success.
- */
-int snd_soc_info_volsw_ext(struct snd_kcontrol *kcontrol,
-	struct snd_ctl_elem_info *uinfo)
-{
-	int max = kcontrol->private_value;
-
-	if (max == 1 && !strstr(kcontrol->id.name, " Volume"))
-		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
-	else
-		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
-
-	uinfo->count = 1;
-	uinfo->value.integer.min = 0;
-	uinfo->value.integer.max = max;
-	return 0;
-}
-EXPORT_SYMBOL_GPL(snd_soc_info_volsw_ext);
-
 /**
  * snd_soc_info_volsw - single mixer info callback
  * @kcontrol: mixer control