[llvm] [RISCV] Vendor Relocations for Xqci extension (PR #135400)

[Fangrui Song via llvm-commits]

MaskRay wrote:

Can you edit the description to describe some properties? Like we create a local symbol and a R_RISCV_VENDOR relocation before another one

https://github.com/llvm/llvm-project/pull/135400