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>

block/src/qcow/mod.rs

@@ -1822,7 +1822,6 @@ pub fn detect_image_type(file: &mut RawFile) -> Result<ImageType> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::io::{Read, Seek, SeekFrom, Write};
     use vmm_sys_util::tempfile::TempFile;
     use vmm_sys_util::write_zeroes::WriteZeroes;
 

block/src/qcow/raw_file.rs

@@ -11,7 +11,6 @@
 use crate::BlockBackend;
 use libc::c_void;
 use std::alloc::{alloc_zeroed, dealloc, Layout};
-use std::convert::TryInto;
 use std::fs::{File, Metadata};
 use std::io::{self, Read, Seek, SeekFrom, Write};
 use std::os::unix::io::{AsRawFd, RawFd};