ASoC: soc-pcm: tidyup soc_pcm_pointer()'s delay update method

Merge series from Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>:

	Current soc_pcm_pointer() is checking runtime->delay,
	but it might be updated silently by component's .point callback.
	It is strange and difficult to find/know the issue.  This patch
	adds .delay callback for component, and solve the issue.