vmm: device_manager: Scan memory devices upon GED interrupt

If there is a GED interrupt and the field indicates that the memory
device has changed triggers a scan of the memory devices.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

devices/src/lib.rs

@@ -75,4 +75,5 @@ pub trait Interrupt: Send + Sync {
 pub enum HotPlugNotificationType {
     NoDevicesChanged,
     CPUDevicesChanged,
+    MemoryDevicesChanged,
 }