block: Move DiskTopology to common code

It doens't make sense to limit this to the async_io module and import
across modules so place in default create module.

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

block/src/raw_sync.rs

@@ -3,8 +3,9 @@
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
 
 use crate::async_io::{
-    AsyncIo, AsyncIoError, AsyncIoResult, DiskFile, DiskFileError, DiskFileResult, DiskTopology,
+    AsyncIo, AsyncIoError, AsyncIoResult, DiskFile, DiskFileError, DiskFileResult,
 };
+use crate::DiskTopology;
 use std::collections::VecDeque;
 use std::fs::File;
 use std::io::{Seek, SeekFrom};