[clang] [llvm] [RISCV] Add more extensions to spacemit-x100 (PR #186351)

[Olaf Bernstein via cfe-commits]

camel-cdr wrote:

@zqb-all Hi, I noticed that some of the SpacemiT cores (not sure if it's A100 only or also X100) support Zvzip like custom instructions (https://www.spacemit.com/community/document/info?nodepath=ai/architecture/ime_extension.md&lang=en chapter 3).
It would be great to get those upstream (asm and intrinsics), as it would allow us to start Zvzip enablement early (macro based abstraction that selects betwren custom and standard Zvzip instructions).

https://github.com/llvm/llvm-project/pull/186351