[mlir] Add arith.addui_carry conversion to LLVM

This covers the scalar and 1-D vector case.

I haven't implemented conversion for the multidimensional vector case yet because
the current LLVM conversion infrastructure (`handleMultidimensionalVectors`) does
not seem to support ops with multiple results.

Reviewed By: Mogball

Differential Revision: https://reviews.llvm.org/D132613