[clang] [llvm] [RISCV] Add processor definition for Spacemit-K1 (PR #94564)

[Pengcheng Wang via cfe-commits]

wangpc-pp wrote:

Spacemit K1 is the name of the product/SoC or whatever you call it. The processor definitions in the RISCV backend are focusing on the CPU core.
For Spacemit K1, its name should be `X60`? I don't know……

https://github.com/llvm/llvm-project/pull/94564