intel_iommu: Add a placeholder variable for scalable mode stage-1 translation

intel_iommu: Add a placeholder variable for scalable mode stage-1 translation

Add an new element flts in IntelIOMMUState to mark stage-1 translation support
in scalable mode, this element will be exposed as an intel_iommu property
x-flts finally.

For now, it's only a placehholder and used for address width compatibility
check and block host device passthrough until nesting is supported.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Clément Mathieu--Drif<clement.mathieu--drif@eviden.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Message-Id: <20241212083757.605022-4-zhenzhong.duan@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>