EFI Code Gets More Cleaning With Linux 5.6

The EFI kernel code has seen a variety of clean-ups and low-level improvements to it for the Linux 5.6 cycle.

Among the EFI work queued for Linux 5.6 is cleaning up of the graphics output (EFI GOP) handling code within the EFI stub, refactoring the mixed mode handling in the x86 EFI stub, overhauling the x86 EFI boot/runtime code, better robustness out of the mixed mode code, support to disable DMA at the root port level, getting rid of RWX mappings in the EFI memory map and page tables where possible, and other fixes and clean-ups.

It's quite a lot of EFI changes for once cycle - much more than we've been used to seeing in recent times on the EFI front. The complete list of EFI changes for Linux 5.6 can be found via this pull request with all the new material.