ARM: meson: odroid-go-ultra: setup PMIC regulators are board init

The Odroid Go Ultra has 2 chained PMICs RK818 and RK818, and needs
an adjustment on the BUCK and LDO values.

Add the initial regulators values in -u-boot.dtsi & run the initial
regulator setup in a new odroid-go-ultra board.

Proper OTG and BOOST regulators are still missing to have USB-A
host properly working.

Link: https://lore.kernel.org/r/20230210-u-boot-odroid-go-ultra-pmics-setup-v1-1-1f16d62b76af@linaro.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>