Revert "[RISCV][CostModel] VPIntrinsics have same cost as their non-vp counterparts (#67178)"

This reverts commit fc865c20.

Triggering assert on X86:

```
iree-compile: /work/third_party/llvm-project/llvm/include/llvm/Support/Casting.h:662: decltype(auto) llvm::dyn_cast(From *) [To = llvm::PointerType, From = llvm::Type]: Assertion `detail::isPresent(Val) && "dyn_cast on a non-existent value"' failed.
```

See PR for comments and full stack trace.