As all level 2 and level 3 caches are unified, add required
cache-unified properties to fix warnings like:
meson-a1-ad401.dtb: l2-cache0: 'cache-unified' is a required property
https://lore.kernel.org/lkml/20230421223211.115612-1-krzysztof.kozlowski@linaro.org/T/
Signed-off-by: Patrick Yavitz <pyavitz@xxxxx.com>
Co-authored-by: Patrick Yavitz <pyavitz@xxxxx.com>
