ASoC: SOF: ipc4-topology: add SoundWire/ALH aggregation support

Some SoundWire hardware topologies rely on different amplifiers or
capture devices connected on different links. These devices need to be
'aggregated', remain synchronized and be handled as a single logical
device.

In the IPC3 solution, the aggregation for amplifiers was handled by a
firmware 'demux' component. In the IPC4 solution, the demux component is
not needed, the gateway component can handle multiple ALH/DMA transfers
at the same time. This change makes the topology slightly more complicated
in that only one ALH DAI will be connected in the topology with the
gateway. The other DAIs that are part of the 'aggregated' dailink are not
shown in the DAPM graph as connected to the gateway, but they will however
be activated thanks to a feature in soc-dapm.c where events are forwarded
to all DAIs in the dailink (see soc_dapm_stream_event).

The topology also sets the same stream name for all widgets, dais and
dailinks, so a search for the stream name helps identify cases where
SoundWire/ALH aggregation is needed.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220614092630.20144-1-yung-chuan.liao@linux.intel.com


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