virtio-devices: Add set_notifier() method to VirtioInterrupt

It is currently left as unimplemented!().

No functional change intended as there are no callers.

Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>

virtio-devices/src/device.rs

@@ -37,6 +37,12 @@ pub trait VirtioInterrupt: Send + Sync {
     fn notifier(&self, _int_type: VirtioInterruptType) -> Option<EventFd> {
         None
     }
+    fn set_notifier(
+        &self,
+        int_type: u32,
+        notifier: Option<EventFd>,
+        vm: &dyn hypervisor::Vm,
+    ) -> std::io::Result<()>;
 }
 
 #[derive(Clone)]