[clang] [llvm] [RISCV] Add Svrsw60t59b extension (PR #132321)

[Mingzhu Yan via llvm-commits]

trdthg wrote:

@topperc sorry for the late reply. I've just fixed all the errors, could you take a look?

(The old spec link is dead, now svrsw60t59b is a part of iommu https://github.com/riscv-non-isa/riscv-iommu/pull/605)

https://github.com/llvm/llvm-project/pull/132321