drm/edid: convert drm_edid_to_sad() to use cea db iter

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