docs: In certain GPU cases, additional configuration may be needed for pass through

[VariableDeclared]

Please describe the question or issue you're facing with "Type: gpu".

When passing through a GPU according to the guide, if a GPU has a large amount of RAM, e.g. 24G - the VM will hang.

raw.qemu: -fw_cfg name=opt/ovmf/X-PciMmio64Mb,string=65536 is required to make the VM work.

For details see #14380 (comment)

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Reported from: https://documentation.ubuntu.com/lxd/en/latest/reference/devices_gpu/

[tomponline]

We should also investigate if we can detect this requirement from lspci (or similar) and auto set these settings.

[github-actions]

Heads up @mionaalex - the "Documentation" label was applied to this issue.