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>

hypervisor/src/arch/emulator/mod.rs

@@ -4,8 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 
-extern crate thiserror;
-
 use core::fmt::Debug;
 use std::fmt::{self, Display};
 use thiserror::Error;