No ack() calback in component driver

Hi Morimoto-san,

With your commit e2cb4a14541d ("ASoC: soc-core: merge snd_pcm_ops member to component driver") snd_pcm_ops is replaced with callback functions in component driver. In doing so, ack() callback was not retained in component driver.

Was this intentional because there were no users of ack() or if there were other reasons?

Thanks, Sameer.