ASoC: imx-es8328: Fix missing return code in imx_es8328_probe()

An error code was forgotten to be passed in the error path of
imx_es8328_probe().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/imx-es8328.c

@@ -104,6 +104,7 @@ static int imx_es8328_probe(struct platform_device *pdev)
 	if (ext_port > MUX_PORT_MAX || ext_port == 0) {
 		dev_err(dev, "mux-ext-port: hardware only has %d mux ports\n",
 			MUX_PORT_MAX);
+		ret = -EINVAL;
 		goto fail;
 	}