Port graphics drivers from Linux 6.8

[alice-sowerby]

User Story

As a user already running a desktop on FreeBSD, I want to be able to upgrade the GPU drivers to the ones ported from Linux 6.8 and still have a working desktop environment:

• I can use a vt(4) session
• I can use my X.Org/Wayland session
• I can play games
• I can watch videos, possibly with hardware-assisted decoding
• I can suspend and resume the computer

GPGPU is out of scope because it is not actively worked on.

Implementation Notes

Acceptance Criteria

• No regressions: if a desktop environment worked with the drivers available in ports/packages, it should continue to work with the drivers from Linux 6.8.
• (optional) An unsupported GPU starts to work

[dumbbell]

Here is the Phoronix article that sums up the DRM-specific changes published in Linux 6.8:
https://www.phoronix.com/news/Linux-6.8-DRM

(I like to add that link in the pull request description to get a grasp of what to expect in that particular version)

[emaste]

Linux 6.8 is the first to officially support the Intel Xe driver (for Gen 12+) although they still use i915 by default.