How so? The claims have very little to do with the diagrams. They are only there as an example processor for the claims being presented. The claims are specifically about cache. More specifically clearing/invalidation. What better way to prevent the competition from implementing something similar than using the competitions architecture as the base to show how it could be implemented? It is Intel's prior art against AMD.
As prior art. You cannot patent things which are not your invention and a prior knowledge. Would be hard to proof it is your invention if you use knowledge from your main competitor in the patent application
They are not trying to patent anything other than their own work. Their work is something which can be added to certain processors(AMD's included). Why not base the example on a competitor's processor so there is less of a chance someone could argue it is reliant on Intel's processor architecture?