Exactly this. AMDs license is not transferable, this has been established and beaten to death.
But how is it not transferable? Recall that the same was said of AMD's ability to make chips using a third-party foundry a few years back... Last I checked, the full details of the AMD-Intel cross licensing agreement were not in the public domain so how can we establish such?
If we go by the original post of this thread of roughly $600M revenue per year for AMD from the xbox one and couple that with the xbox360 averaging 10M units per year we're left with that roughly $60 per unit figure going to AMD. That definitely implies that they're delivering actual silicon instead of IP since that would be an extremely high IP charge... in which case I'd certainly hope that they're able to fab it at GF to negate any possibility of a WSA charge since $60 per chip would probably be at or below a 30% gross margin.
Edit: Of course, that assumes that the $3B figure is spread over only 5 years. But the source merely says 'multi-year' worth "$3+B" - that could be over 3 years or 10. But if that figure is for the entire lifetime of the xbox one and it surpasses 100M units then you're already down to $30 each... though Microsoft is having fun estimating far higher figures than that due in part to the non-traditional (aka non-gaming) uses for the console. And once you get into those kind of numbers you're definitely talking IP royalties, not silicon.