fixup: arm: rockchip: Add RK3576 arch core support - u-boot.dtsi

- add minimal rng node, see [1] for driver
- add minimal otp node instead of picking an unmerged dts/upstream patch
- add missing emmc_rstnout, sdmmc0_pwren and pcfg_pull_up_drv_level_3
  pinctrl nodes
- add missing ioc_grf to fix use of pinctrl in SPL
- remove bootph props from unreferenced pcfg_pull_down and php_grf nodes
- adjust bootph for uart pinctrl to save a few ms boot time

[1] https://patchwork.ozlabs.org/patch/2038156/