Merge https://source.denx.de/u-boot/custodians/u-boot-riscv

CI: https://source.denx.de/u-boot/custodians/u-boot-riscv/-/pipelines/20596

- RISC-V: cmd: Add SBI implementation ID and extension ID
- Board: Rename spl_soc_init to spl_dram_init
- Board: milkv_duo: Add SPI NOR flash, Ethernet, Sysreset support