Use the cea db iterator for short audio descriptors. We'll still stop at
the first audio data block, but not at the first CTA Extension if that
doesn't have the info.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/237e4b1de1567903d37ce1d1bb830020b8fd6690.1651569697.git.jani.nikula@intel.com