ASoC: intel/skl/hda - export number of digital microphones via control components

It is required for the auto-detection in the user space (for UCM).

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20191204211556.12671-2-pierre-louis.bossart@linux.intel.com


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