The CHAIN_DMA IPC needs the number of playback streams as a start
offset for the dma_id of a capture stream.

This offset can be retrieved on Intel platforms from the GCAP
information, and stored in the sof_ipc4_fw_data structure.

One could argue that the fields added are not really dependent on any
firmware definitions but rather on hardware capabilities, but they are
required for the IPC CHAIN_DMA definitions so adding them in
ipc4_fw_data isn't completely silly.

The CHAIN_DMA IPC is currently only functional on Intel HDaudio DMAs,
and gated by the snd_sof_is_chain_dma_supported() helper.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://msgid.link/r/20240213101247.28887-6-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>