[llvm] [RISCV] Add the CSR names from Smrnmi. (PR #83370)

[Wang Pengcheng via llvm-commits]

https://github.com/wangpc-pp approved this pull request.

Smrnmi is frozen just now: https://github.com/riscv/riscv-isa-manual/commit/a4382e9c8e285360a88d8056c1253e1525552393


https://github.com/llvm/llvm-project/pull/83370