style, vfs: remove unused imports and InodeRef

Signed-off-by: greatbridf <greatbridf@icloud.com>

src/kernel/vfs/inode/inode.rs

@@ -321,11 +321,6 @@ pub struct InodeInfo {
     pub mtime: Instant,
 }
 
-#[derive(Clone)]
-pub struct InodeRef<I>(Weak<I>)
-where
-    I: Inode + ?Sized;
-
 pub struct InodeUse<I>(Arc<I>)
 where
     I: Inode + ?Sized;

src/kernel/vfs/inode/mod.rs

@@ -4,7 +4,5 @@ mod ops;
 mod statx;
 
 pub use ino::Ino;
-pub use inode::{
-    Inode, InodeDir, InodeDirOps, InodeFile, InodeFileOps, InodeInfo, InodeOps, InodeRef, InodeUse,
-};
+pub use inode::{Inode, InodeDirOps, InodeFileOps, InodeInfo, InodeOps, InodeUse};
 pub use ops::{RenameData, WriteOffset};