arm64: dts: rockchip: Add vdd_cpu_big regulators to rk3588-rock-5b

The RK8602 and RK8603 voltage regulators on the Rock 5B board provide
the power lines vdd_cpu_big0 and vdd_cpu_big1, respectively.

Add the necessary device tree nodes and bind them to the corresponding
CPU big core nodes.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Link: https://lore.kernel.org/r/20230414125425.124994-4-cristian.ciocaltea@collabora.com


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