[clang] [llvm] [RISCV] Make zvknha a subset of zvknhb (PR #178680)

[Ramkumar Ramachandra via cfe-commits]

artagnon wrote:

> What is the advantage of making this change?

It would simplify application code, which checks "zvknha or zvknhb" when zvknha is needed. Besides, zvkng would include zvknha, which I think is intended.

> zvknha and zvknhb are mutually exclusive [riscv/riscv-crypto#364 (comment)](https://github.com/riscv/riscv-crypto/issues/364#issuecomment-1726782096)

I don't understand the comment: the table is quite clear?

https://github.com/llvm/llvm-project/pull/178680