Move Cloud Hypervisor to virtio-queue crate

Relying on the vm-virtio/virtio-queue crate from rust-vmm which has been
copied inside the Cloud Hypervisor tree, the entire codebase is moved to
the new definition of a Queue and other related structures.

The reason for this move is to follow the upstream until we get some
agreement for the patches that we need on top of that to make it
properly work with Cloud Hypervisor.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vm-virtio/src/lib.rs

@@ -10,17 +10,11 @@
 
 //! Implements virtio queues
 
-#[macro_use]
-extern crate log;
-
 use std::fmt;
 
 pub mod queue;
 pub use queue::*;
 
-pub type VirtioIommuRemapping =
-    Box<dyn Fn(u64) -> std::result::Result<u64, std::io::Error> + Send + Sync>;
-
 pub const VIRTIO_MSI_NO_VECTOR: u16 = 0xffff;
 
 // Types taken from linux/virtio_ids.h