virt: move smartcard device to vmdevices.py

No real code changes

Change-Id: I0a5cb5140302b9b909750c7f5df4d257958bab3d
Signed-off-by: Martin Polednik <mpolednik@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/34250
Reviewed-by: Francesco Romani <fromani@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>