dt-bindings: misc: Convert IDT 89HPESx to DT schema

Convert the IDT 89HPESx device binding to DT schema format.

"onsemi,24c64" was not a documented compatible string, so update the
example to "atmel,24c64". It's not clear what's in use here as no
upstream dts files have the eeprom child node.

Acked-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20221005212631.122145-1-robh@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>