virtio-devices: wire driver_status to EpollHandler

Signed-off-by: Peter Oskolkov <posk@google.com>

fuzz/fuzz_targets/block.rs

@@ -95,6 +95,7 @@ fuzz_target!(|bytes: &[u8]| -> Corpus {
             mem: guest_memory,
             interrupt_cb: Arc::new(NoopVirtioInterrupt {}),
             queues: vec![(0, q, evt)],
+            device_status: Arc::new(std::sync::atomic::AtomicU8::new(0)),
         })
         .ok();