It's all internal to intel_audio.c.

Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NLucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211104161858.21786-4-jani.nikula@intel.com