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/vsock/csm/txbuf.rs

@@ -146,8 +146,8 @@ impl TxBuf {
 mod tests {
     use super::*;
     use std::io::Error as IoError;
+    use std::io::ErrorKind;
     use std::io::Result as IoResult;
-    use std::io::{ErrorKind, Write};
 
     struct TestSink {
         data: Vec<u8>,