ASoC: soc-dapm: add snd_soc_dapm_stream_stop()

When we stop stream, if it was Playback, we might need to care
about power down time. In such case, we need to use delayed work.

We have same implementation for it at soc-pcm.c and soc-compress.c,
but we don't want to have duplicate code.
This patch adds snd_soc_dapm_stream_stop(), and share same code.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-By: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/871rs8t4uw.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>