This reverts commit ad57e10dbca2fdeff1448afc0aa1cf23d6df8736 and 1967fd8d5e7e40a987d8f65d163c7eb8f4b9e76f
llvm/lib/Support/RISCVVIntrinsicUtils.cpp introduced llvm/TableGen includes,
a circular dependency https://llvm.org/docs/CodingStandards.html#library-layering
I think this particular instance is serious and should be reverted.