ASoC: mediatek: mt8188-mt6359: clean up a return in codec_init

This code triggers a Smatch static checker warning and does sort of
look like an error path.

sound/soc/mediatek/mt8188/mt8188-mt6359.c:597 mt8188_max98390_codec_init() warn: missing error code? 'ret'

However, returning 0 is intentional.  Make that explicit.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20230608084727.74403-3-angelogioacchino.delregno@collabora.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/mediatek/mt8188/mt8188-mt6359.c

@@ -594,7 +594,7 @@ static int mt8188_max98390_codec_init(struct snd_soc_pcm_runtime *rtd)
 	}
 
 	if (rtd->dai_link->num_codecs <= 2)
-		return ret;
+		return 0;
 
 	/* add widgets/controls/dapm for rear speakers */
 	ret = snd_soc_dapm_new_controls(&card->dapm, mt8188_rear_spk_widgets,