ASoC: Intel: sof-rt5682: add dmic dapm widget to support dmic PCM

We need add DAPM MIC endpoint widget "SoC DMIC" and route, to enable
DMIC PCM DAPM support.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190809232236.21182-3-pierre-louis.bossart@linux.intel.com


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