[Ryzen 4700U, rx 6800XT, Steam Deck] Cursor bugs with hardware rotation

There's two problems I see with the primary plane rotation property being set to rotate-180 or rotate-270:

1. when CRTC_X or CRTC_Y of the cursor plane are negative, the whole cursor plane turns invisible
2. in the middle of the screen, the cursor plane gets clipped off. In some other places, there's even a stripe of the cursor appearing where it gets clipped off in the middle

Neither of these artifacts happen with rotate-0 or rotate-90.

This was discovered in the context of https://invent.kde.org/plasma/kwin/-/merge_requests/2269, which I patched to make the buffer for the cursor plane have a white background instead of transparency. This shows exactly what's happening: VID_20221103_180716