arm64: dts: rockchip: add rk3588 cache level information

Add missing, mandatory cache-level information for RK3588.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230317174102.61209-1-sebastian.reichel@collabora.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>