misc: hypervisor: drop extern crate, use modern rust

This commit is part of a series of similar commits.

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com

hypervisor/src/cpu.rs

@@ -12,7 +12,7 @@
 
 use thiserror::Error;
 #[cfg(not(target_arch = "riscv64"))]
-use vm_memory::GuestAddress;
+use {anyhow::anyhow, vm_memory::GuestAddress};
 
 #[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))]
 use crate::RegList;