ALSA: hda: Allow for compress stream to hdac_ext_stream assignment

ALSA: hda: Allow for compress stream to hdac_ext_stream assignment

Currently only PCM streams can enlist hdac_stream for their data
transfer. Add cstream field to hdac_ext_stream to expose possibility of
compress stream assignment in place of PCM one.
Limited to HOST-type only as there no other users on the horizon.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20221202152841.672536-2-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>