ASoC: tas2552: Make the enable-gpio really optional

Do not fail the probe if the enable-gpio is not specifiedbut handle
deferred probe case.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/codecs/tas2552.c

@@ -486,8 +486,12 @@ static int tas2552_probe(struct i2c_client *client,
 		return -ENOMEM;
 
 	data->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
-	if (IS_ERR(data->enable_gpio))
-		return PTR_ERR(data->enable_gpio);
+	if (IS_ERR(data->enable_gpio)) {
+		if (PTR_ERR(data->enable_gpio) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		data->enable_gpio = NULL;;
+	}
 
 	data->tas2552_client = client;
 	data->regmap = devm_regmap_init_i2c(client, &tas2552_regmap_config);