[clang] [RISCV] Add processor definition for XiangShan-NanHu (PR #70294)

[Yinan Xu via cfe-commits]

poemonsense wrote:

> @dtcxzyw Could you please confirm the status of this core - is it commercially available, an academic test chip, something else?

It's maintained by Beijing Institute of Open Source Chip (BOSC), a non-profit organziation founded by companies and researech institutions. It is provided as an open-source CPU Core IP to the third party. It's not an academic testchip.

It's not commercially available now, but there have already been a couple of companies using it as the CPU Core IP. I cannot disclose the progress of commercial chips now but hopefully we will see it soon. There are also some companies using it on FPGAs now.

https://github.com/llvm/llvm-project/pull/70294