ASoC: soc-dai.h: add snd_soc_dai_get/set_widget_playback/capture() helper

snd_soc_dai_get_widget() requests SNDRV_PCM_STREAM_PLAYBACK/CAPTURE.
This patch adds helper for it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/877cx3foqz.wl-kuninori.morimoto.gx@renesas.com


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