misc: Remove unnecessary "extern crate"

Now all crates use edition = "2018" then the majority of the "extern
crate" statements can be removed. Only those for importing macros need
to remain.

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

pci/src/lib.rs

@@ -5,12 +5,8 @@
 //! Implements pci devices and busses.
 #[macro_use]
 extern crate log;
-extern crate hypervisor;
-extern crate serde;
 #[macro_use]
 extern crate serde_derive;
-extern crate serde_json;
-extern crate vm_memory;
 
 mod bus;
 mod configuration;

pci/src/msi.rs

@@ -3,9 +3,6 @@
 // SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
 //
 
-extern crate byteorder;
-extern crate vm_memory;
-
 use byteorder::{ByteOrder, LittleEndian};
 use std::sync::Arc;
 use vm_device::interrupt::{

pci/src/msix.rs

@@ -3,9 +3,6 @@
 // SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
 //
 
-extern crate byteorder;
-extern crate vm_memory;
-
 use crate::{PciCapability, PciCapabilityId};
 use anyhow::anyhow;
 use byteorder::{ByteOrder, LittleEndian};

pci/src/vfio.rs

@@ -3,8 +3,6 @@
 // SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
 //
 
-extern crate vm_allocator;
-
 use crate::{
     msi_num_enabled_vectors, BarReprogrammingParams, MsiConfig, MsixCap, MsixConfig,
     PciBarConfiguration, PciBarRegionType, PciCapabilityId, PciClassCode, PciConfiguration,