arm64: dts: socionext: add missing cache properties

As all level 2 and level 3 caches are unified, add required
cache-unified property to fix warnings like:

  uniphier-ld11-ref.dtb: l2-cache: 'cache-unified' is a required property

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/20231023021221.2884828-3-hayashi.kunihiko@socionext.com


Signed-off-by: Arnd Bergmann <arnd@arndb.de>