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

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

Iterate through all CTA data blocks across all CTA extensions and
DisplayID data blocks. This may gather more data than before, and if
there's duplicated data, some is overwritten by whichever comes last.

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/8bdc67aa731857111eddd08a9c192d41d40b5f5a.1651569697.git.jani.nikula@intel.com