Merge tag 'u-boot-rockchip-20240525' of https://source.denx.de/u-boot/custodians/u-boot-rockchip

CI: https://source.denx.de/u-boot/custodians/u-boot-rockchip/-/pipelines/20844

- new board: rk3566 Powkiddy X55, rk3588s Indiedroid Nova;
- rv1126 migrate to OF_UPSTREAM;
- Fix for px30 ringneck board;
- Fix for rk3588 SPLL clock init;