[RISCV] Infer mask type for vector intrinsics from the data type

We can use LLVMScalarOrSameVectorWidth<0, llvm_i1_ty> to infer the mask type from the anyvector_ty. This will save us from needing to pass it to getDeclaration when creating these intrinsics from clang.

No tests updates are needed because our declarations are exploiting a behavior in the IR parser where the declaration of an intrinsic doesn't need to mention all the types as long as there isn't a name conflict in the file.

Reviewed By: khchen

Differential Revision: https://reviews.llvm.org/D93409