ASoC: Intel: avs: Machine board registration

AVS driver operates with granular audio card division in mind.
Super-card approach (e.g.: I2S, DMIC and HDA DAIs combined) is
deprecated in favour of individual cards - one per each device. This
provides necessary dynamism, especially for configurations with number
of codecs present and makes it easier to survive auxiliary devices
failures - one card failing to probe does not prevent others from
succeeding.

All boards spawned by AVS are unregistered on ->remove(). This includes
dummy codecs such as DMIC.

As all machine boards found in sound/soc/intel/boards are irreversibly
tied to 'super-card' approach, new boards are going to be introduced.
This temporarily increases number of boards available under /intel
directory until skylake-driver becomes deprecated and removed.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220516101116.190192-12-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>