Ocean currents haven't changed for a few thousand years. They could have hit the Caribbean but it's possible they could have gotten to Florida/Georgia/South Carolina on the North Equatorial current.
It's within the realm of possibility but I think it's unlikely for a lot of reasons. First, this is the position of the empire relative to those currents:
1. On the north, the empire pretty much went straight up to the edge of the desert and then stopped. They might have probed even further north to find those currents, but seems more likely they would have probed south instead. That would have directed them to the South American coast.
2. If they went north, they would have had a much longer journey = less chance for success. So even if they did got north, rather than south, there's a decent chance they never made it. We have no idea what they were expecting to prepare for, how long they expected it to be, but it would have been many times longer over open ocean than anything they would have done before.
3. Even Columbus coming from far further north 200 years later hit Bahamas, Hispanola, Cuba, Jamaica, Puerto Rico every time on 4 separate tries with different routes every time, never Florida/Georgia. From there his explorations reached Mexico, Honduras, Nicaragua, Costa Rica and Panama, but never the USA. The Mali empire would have come along the extreme southern end of those currents, so they'd be even more likely to hit the Caribbean first.
4. When early Europeans missed the Caribbean, they always ended up way to the north instead, ending up in Canada every time. Norsemen in the 1000s, João Vaz Corte-Real in the 1400s (speculative), John Cabot in 1497, João Fernandes Lavrador in 1499, Corte-Real brothers in 1501, they ALL hit Canada, not the USA.
5. Ponce de Leon finally hit Florida in 1512, after conquering Cuba. This was after 20+ years of European exploration and after 10+ separate journeys, and he found it VIA Cuba, not by skipping.
6. The potential evidence we do have for Africans landing in the Americas pre-Columbus all comes from Central/South America or the Caribbean. I'm not aware of any evidence from USA territory that anyone serious takes seriously.
I think there's a reasonable chance African explorers found their way to Latin America, but very unlikely to be the USA for the same reasons that everyone else hit Latin America first too, even though the others were coming from even further north than the Africans would have.