ASoC: fsl_easrc: Fix event generation in fsl_easrc_iec958_put_bits()

ALSA controls should return 1 if the value in the control changed but the
control put operation fsl_easrc_iec958_put_bits() unconditionally returns
0, causing ALSA to not generate any change events. This is detected by
mixer-test with large numbers of messages in the form:

    No event generated for Context 3 IEC958 CS5
    Context 3 IEC958 CS5.0 orig 5224 read 5225, is_volatile 0

Add a suitable check.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://patch.msgid.link/20260205-asoc-fsl-easrc-fix-events-v1-1-39d4c766918b@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: broonie

sound/soc/fsl/fsl_easrc.c

@@ -52,10 +52,13 @@ static int fsl_easrc_iec958_put_bits(struct snd_kcontrol *kcontrol,
 	struct soc_mreg_control *mc =
 		(struct soc_mreg_control *)kcontrol->private_value;
 	unsigned int regval = ucontrol->value.integer.value[0];
+	int ret;
+
+	ret = (easrc_priv->bps_iec958[mc->regbase] != regval);
 
 	easrc_priv->bps_iec958[mc->regbase] = regval;
 
-	return 0;
+	return ret;
 }
 
 static int fsl_easrc_iec958_get_bits(struct snd_kcontrol *kcontrol,