misc: Remove redundant "use" imports

With the nightly toolchain (2024-02-18) cargo check will flag up
redundant imports either because they are pulled in by the prelude on
earlier match.

Remove those redundant imports.

Signed-off-by: Rob Bradford <rbradford@rivosinc.com>

virtio-devices/src/lib.rs

@@ -16,7 +16,6 @@ extern crate event_monitor;
 extern crate log;
 
 use serde::{Deserialize, Serialize};
-use std::convert::TryInto;
 use std::io;
 use thiserror::Error;