Fix imports

src/sync/mpsc.rs

@@ -82,13 +82,13 @@ pub fn channel<T>() -> (Sender<T>, Receiver<T>) {
     (sender, receiver)
 }
 
-use alloc::boxed::Box;
-use super::*;
-use thread;
-
 pub mod test {
     //! Copied from std::mpsc::test
 
+    use alloc::boxed::Box;
+    use super::*;
+    use thread;
+
     fn smoke() {
         let (tx, rx) = channel::<i32>();
         tx.send(1).unwrap();