Even taking a literalist approach to the Garden of Eden, the range of various lion species was far greater in the past then it stands currently. There were lions in Europe and the New World, as well as Asia (there are still Asian lions, though they have a limited range). And that is assuming a rather strict definition of lion - I doubt that current taxonomic classifications was used in the Bible.
Lions were found outside Africa--a famous ruin from Bronze Age Greece is the Lion Gate at Mycenae, and one of the labors of Hercules (Heracles) involved the Nemean Lion (Nemea is in Greece). The ancient Persians had the lion for a symbol. And if the Garden of Eden was in Africa, how did Adam name the kangaroo, the koala, and the wallaby? Not to mention the Komodo dragon or the Gila monster.