vfio/ap: Use vfio_[attach/detach]_device

vfio/ap: Use vfio_[attach/detach]_device

Let the vfio-ap device use vfio_attach_device() and
vfio_detach_device(), hence hiding the details of the used
IOMMU backend.

We take the opportunity to use g_path_get_basename() which
is prefered, as suggested by
3e015d815b ("use g_path_get_basename instead of basename")

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>