docs: Fix version that introduced Xen support for ACPI firmware
docs: Fix version that introduced Xen support for ACPI firmware

Xen support for specifying ACPI firmware path was introduced in the
5.9.0 dev cycle, not 5.8.0 as currently indicated by the docs.

Signed-off-by: Jim Fehlig <39929b5b86d72d51fceac59b52303e3fe8a3083e@suse.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

jardasgit/libvirt,zippy2/libvirt,jardasgit/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,olafhering/libvirt,olafhering/libvirt,nertpinx/libvirt,libvirt/libvirt,nertpinx/libvirt,libvirt/libvirt,fabianfreyer/libvirt,crobinso/libvirt,jfehlig/libvirt,zippy2/libvirt,fabianfreyer/libvirt,zippy2/libvirt,crobinso/libvirt,crobinso/libvirt,jfehlig/libvirt,crobinso/libvirt,olafhering/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,nertpinx/libvirt,jardasgit/libvirt,zippy2/libvirt,olafhering/libvirt,nertpinx/libvirt,jardasgit/libvirt,nertpinx/libvirt,libvirt/libvirt,libvirt/libvirt