ASoC: mediatek: simplify the return expression of mtk_dai_pcm_prepare()

Simplify the return expression.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Link: https://lore.kernel.org/r/20220505021808.54337-1-chi.minghao@zte.com.cn


Signed-off-by: Mark Brown <broonie@kernel.org>