virtio-bindings: Add virtio bindgen generated bindings

This is copied from crosvm, commit 107edb3e.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

virtio-bindings/src/lib.rs

@@ -0,0 +1,15 @@
+// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Portions Copyright 2017 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the THIRD-PARTY file.
+
+#![allow(clippy::all)]
+#![allow(non_upper_case_globals)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+
+pub mod virtio_blk;
+pub mod virtio_net;
+pub mod virtio_ring;