[Fixed] 5k 120hz bug in nvidia driver?

[rvdende]

Vive Pro 2 — 4896x2448 DSC modes render the left half of the framebuffer on both eyes (NVIDIA)

Working notes for #65.

Status: ROOT CAUSE FOUND AND FIXED. It is not a DSC bug. It is a 2Heads1OR (merge mode)
viewport bug in nvidia-modeset: at modeset time every hardware head has its viewport origin
hardcoded to x=0, ignoring mergeHeadSection, so both merge heads scan out the left half of the
framebuffer. One-line fix, verified working at 4896x2448@120 on a HTC Vive Pro 2

[rvdende]

Got it working! Here is my PR to nvidia https://github.com/NVIDIA/open-gpu-kernel-modules/pull/1262/changes
5k 120fps is so worth it by the way!