[RFC] Remove codegen support for trivial VP intrinsics in the RISC-V backend

[lukel]

After [RISCV] Remove codegen for vp_and, vp_or, vp_xor, vp_sra, vp_srl, vp_shl. NFC by lukel97 · Pull Request #194904 · llvm/llvm-project · GitHub, the codegen for all trivial VP intrinsics has been removed from the RISC-V backend, and the intrinsics are expanded instead to their equivalent plain LLVM IR.