Levi loves cat poop too.
We don't have a cat, but we do have an annoying neighbor that lets her cat roam around alone and poop wherever it pleases outdoors. We are on constant cat poop watching duty when we're outside. Gross.
I like the suggestion about moving the cat's litter box to where the cat can reach it but the Yorkie can't. I'd be concerned about your pup ingesting too much cat litter.