drm/edid: sunset the old unused cea data block iterators

All CTA data block iteration has now been converted to the new cea db
iterators.

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/a5b35ed0e711bd874f76ae87ee0b70150d0a77c4.1651569697.git.jani.nikula@intel.com