Rebased 6.12.y-gpu branch with the upstream RPi kernel

[RSC-Games]

Since this is like the official repository with all the known working patches, I'd like to push the changes here rather than keep them separate in my own fork. However, if you'd rather me maintain them in my fork, let me know. I've still got a lot of work to do on the kernel concerning IOMMU2 and PCIe passthrough.