rust: enable `clippy::unnecessary_safety_comment` lint

In Rust 1.67.0, Clippy added the `unnecessary_safety_comment` lint [1],
which is the "inverse" of `undocumented_unsafe_blocks`: it finds places
where safe code has a `// SAFETY` comment attached.

The lint currently finds 3 places where we had such mistakes, thus it
seems already quite useful.

Thus clean those and enable it.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#/unnecessary_safety_comment [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Tested-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240904204347.168520-6-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index 3021f30fd822..84c7cbfb096d 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -341,7 +341,7 @@ impl<T: 'static> ForeignOwnable for Arc<T> {
     }
 
     unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> ArcBorrow<'a, T> {
-        // SAFETY: By the safety requirement of this function, we know that `ptr` came from
+        // By the safety requirement of this function, we know that `ptr` came from
         // a previous call to `Arc::into_foreign`.
         let inner = NonNull::new(ptr as *mut ArcInner<T>).unwrap();