Add SBI requirements for server platforms that are a superset of BRS ones

[andreiw]

Looking at SBI 3.0 extensions, wherever required and matching Server SoC hardware requirements (e.g. RAS)

[andreiw]

Another example is hosted/native debug extension.

Need to scan the Server SoC requirements and identify the new SBI requirements that don't exist in the BRS.

[andreiw]

For RAS looks like we just need https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-sse.adoc so far....