[llvm] [RISCV] Change RISCVMCExpr::VK_RISCV_None to RISCVMCExpr::VK_None (PR #131774)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

If either of the windows or linux build has already passed, a fixup like this should be good to go.

https://github.com/llvm/llvm-project/pull/131774