[clang] [llvm] [RISCV] Add Qualcomm uC Xqcisim (Simulation Hint) extension (PR #128833)

[Sam Elliott via llvm-commits]

https://github.com/lenary approved this pull request.

LGTM.

I think we've given plenty of time for further comments on supporting this extension (or not), and given last I heard on the call that @asb was happy for this to land, I think we should proceed.

https://github.com/llvm/llvm-project/pull/128833