virtio_ring: Cut and paste bugs in vring_create_virtqueue_packed()

There is a copy and paste bug in the error handling of this code and
it uses "ring_dma_addr" three times instead of "device_event_dma_addr"
and "driver_event_dma_addr".

Fixes: 1ce9e605

 (" virtio_ring: introduce packed ring support")
Reported-by: Robert Buhren <robert.buhren@sect.tu-berlin.de>
Reported-by: Felicitas Hetzelt <file@sect.tu-berlin.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/X8pGRJlEzyn+04u2@mwanda


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>