vsock/virtio: fix src/dst cid format

commit f83f12d6 upstream.

These fields are 64 bit, using le32_to_cpu and friends
on these will not do the right thing.
Fix this up.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>