[MLIR][LLVM] Permit integer types in switch other than i32

[MLIR][LLVM] Permit integer types in switch other than i32

LLVM switchop currently only permits i32. Both LLVM IR and MLIR Standard switch permit other integer types leading to an illegal state when lowering an i8 switch from MLIR standard

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D113955