refactor(uu/rm): simplify device skipping logic by removing wrapper function

Remove the cfg-specific `should_skip_different_device` wrapper and directly call
`should_skip_different_device_with_dev` with a `#[cfg(unix)]` attribute in the
recursive directory removal function, reducing code duplication and improving clarity.

Author: mattsu2020

src/uu/rm/src/rm.rs

@@ -611,26 +611,6 @@ fn is_writable(_path: &Path) -> bool {
     true
 }
 
-#[cfg(unix)]
-fn should_skip_different_device(
-    parent_dev_id: Option<u64>,
-    metadata: &Metadata,
-    options: &Options,
-    path: &Path,
-) -> bool {
-    should_skip_different_device_with_dev(parent_dev_id, metadata.dev(), options, path)
-}
-
-#[cfg(not(unix))]
-fn should_skip_different_device(
-    _parent_dev_id: Option<u64>,
-    _metadata: &Metadata,
-    _options: &Options,
-    _path: &Path,
-) -> bool {
-    false
-}
-
 #[cfg(unix)]
 fn should_skip_different_device_with_dev(
     parent_dev_id: Option<u64>,
@@ -759,7 +739,8 @@ fn remove_dir_recursive_with_metadata(
     }
 
     // Base case 3: this is a directory on a different device
-    if should_skip_different_device(parent_dev_id, metadata, options, path) {
+    #[cfg(unix)]
+    if should_skip_different_device_with_dev(parent_dev_id, metadata.dev(), options, path) {
         return true;
     }