vfio/container: Modify vfio_get_iommu_type() to use a container fd The 'container' pointer has no other use than its 'fd' attribute. Simplify the prototype to ease future changes. Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Cédric Le Goater <clg@redhat.com>