vm-virtio: Add IOMMU support to virtio-vsock

Adding virtio feature VIRTIO_F_IOMMU_PLATFORM when explicitly asked by
the user. The need for this feature is to be able to attach the virtio
device to a virtual IOMMU.

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

vm-virtio/src/vsock/mod.rs

@@ -256,7 +256,7 @@ mod tests {
                 cid: CID,
                 mem: GuestMemoryMmap::new(&[(GuestAddress(0), MEM_SIZE)]).unwrap(),
                 mem_size: MEM_SIZE,
-                device: Vsock::new(CID, TestBackend::new()).unwrap(),
+                device: Vsock::new(CID, TestBackend::new(), false).unwrap(),
             }
         }