ASoC: madera: Fix event generation for rate controls

madera_adsp_rate_put always returns zero regardless of if the control
value was updated. This results in missing notifications to user-space
of the control change. Update the handling to return 1 when the
value is changed.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220623105120.1981154-5-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/madera.c

@@ -899,7 +899,7 @@ static int madera_adsp_rate_put(struct snd_kcontrol *kcontrol,
 	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
 	const int adsp_num = e->shift_l;
 	const unsigned int item = ucontrol->value.enumerated.item[0];
-	int ret;
+	int ret = 0;
 
 	if (item >= e->items)
 		return -EINVAL;
@@ -916,10 +916,10 @@ static int madera_adsp_rate_put(struct snd_kcontrol *kcontrol,
 			 "Cannot change '%s' while in use by active audio paths\n",
 			 kcontrol->id.name);
 		ret = -EBUSY;
-	} else {
+	} else if (priv->adsp_rate_cache[adsp_num] != e->values[item]) {
 		/* Volatile register so defer until the codec is powered up */
 		priv->adsp_rate_cache[adsp_num] = e->values[item];
-		ret = 0;
+		ret = 1;
 	}
 
 	mutex_unlock(&priv->rate_lock);