ASoC: Intel: bytcr_rt5640: Add a byt_rt5640_get_codec_dai() helper

Add a byt_rt5640_get_codec_dai() helper, which gets the codec_dai
from a dapm_context.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210802142501.991985-4-hdegoede@redhat.com


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