[llvm] [RISCV] Macro-fusion support for veyron-v1 CPU. (PR #70012)

[Wang Pengcheng via llvm-commits]

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

I'd like to see this landed so that there are more use cases for TableGen way. :-)

https://github.com/llvm/llvm-project/pull/70012