Comment 36 for bug 1805920

To keep potential regressions even lower I'd for now only consider that for >=Bionic.
That also helps as if someone intentionally spawns an old type KVM machine (pre Bionic) on a >=Bionic host we don#t have to care about this too much (machine type, not release runnin IN the guest). That makes us able to ignore ipxe-qemu-256k-compat-efi-roms in regard to this issue.