fbdevhw: kernel >=v6.9 breaks fbdev_open()

First found in Debian's automated ISO QA Testing infrastructure [0] and confirmed due to recent Linux kernel changes [1] in the sysfs path of the parent device.

The framebuffer device's symlink now points to the parent PCI device which breaks detection. I'm sending a patch to xorg-devel@ which changes this to use the subsystem node instead.

Kernel v6.8:

[    14.067] (II) fbdev_open() sysfs_path=/sys/class/graphics/fb0
[    14.067] (II) fbdev_open() buf=../../devices/platform/vesa-framebuffer.0/graphics/fb0

Kernel v6.9

[    15.609] (II) fbdev_open() sysfs_path=/sys/class/graphics/fb0
[    15.609] (II) fbdev_open() buf=../../devices/pci0000:00/0000:00:01.0/vesa-framebuffer.0/graphics/fb0

[0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1075713

[1] https://lore.kernel.org/lkml/lLyvPFC_APGHNfyGNHRpQy5izBikkaTPOpHooZIT3fFAoJPquSI31ZMueA99XTdr8ysir3X7O7IMdc6za-0m79vr_claeparHhoRouVgHOI=@proton.me/

Patch sent to xorg-devel@

0001-fbdevhw-fix-sysfs-path-PCI-device-detection.patch