virtio/queue: Allow clippy::unnecessary_map_or

clippy suggests replacing map_or with is_none_or, which is an unstable
library feature at time of commit. Silence this warning and allow the
use of map_or for the time being.

Signed-off-by: Tyler Fanelli <[email protected]>

Author: tylerfanelli

src/devices/src/virtio/queue.rs

@@ -378,6 +378,7 @@ impl Queue {
         min(self.size, self.max_size)
     }
 
+    #[allow(clippy::unnecessary_map_or)]
     pub fn is_valid(&self, mem: &GuestMemoryMmap) -> bool {
         let queue_size = u64::from(self.actual_size());
         let desc_table = self.desc_table;