Before we really unregister the hwrng device, reading will get stuck if
the virtio device is reset. We should return error for reading when we
start to remove the device.
Signed-off-by: NAmos Kong <akong@redhat.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>