rust: fmt: fix {:p} printing stack addresses

The `impl_fmt_adapter_forward!` macro forwards `Pointer` for
`Adapter<T>` by destructuring `self` into a local `t`, causing `{:p}`
to print the address of that temporary stack variable rather than the
actual pointer.

Remove `Pointer` from the macro and provide a manual impl for
`Adapter<&T>` that passes `self.0` directly.

Signed-off-by: Ke Sun <sunke@kylinos.cn>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Tested-by: Link Mauve <linkmauve@linkmauve.fr>
Cc: stable@vger.kernel.org
Fixes: c5cf01b ("rust: support formatting of foreign types")
Link: https://patch.msgid.link/20260810-hashedptr-v15-1-eafd27d36476@kylinos.cn
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: alvinsun039

rust/kernel/fmt.rs

@@ -43,7 +43,14 @@ use core::fmt::{
     UpperExp,
     UpperHex, //
 };
-impl_fmt_adapter_forward!(Debug, LowerHex, UpperHex, Octal, Binary, Pointer, LowerExp, UpperExp);
+impl_fmt_adapter_forward!(Debug, LowerHex, UpperHex, Octal, Binary, LowerExp, UpperExp);
+
+impl<T: ?Sized + Pointer> Pointer for Adapter<&T> {
+    #[inline]
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        Pointer::fmt(self.0, f)
+    }
+}
 
 /// A copy of [`core::fmt::Display`] that allows us to implement it for foreign types.
 ///