[llvm] [RISCV] Add groupid/bitmask for RISC-V extension (PR #94440)

[Pengcheng Wang via llvm-commits]

https://github.com/wangpc-pp commented:

You can add tests to `llvm/test/TableGen/riscv-target-def.td`.

https://github.com/llvm/llvm-project/pull/94440