samples: work-philosophers: Fox Mutex lock missing on stats

The stats is returned still in the Arc<Mutex<_>> to avoid an extra copy
of the large stat structure.

Add the lock to allow for this.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

samples/work-philosophers/src/lib.rs

@@ -63,7 +63,7 @@ extern "C" fn rust_main() {
     let handle = spawn(hand_sem::phil(&worker), &worker, c"hand-sem");
     let stats = handle.join();
     printkln!("Done with hand-sem test");
-    stats.show();
+    stats.lock().unwrap().show();
 
     // First run the async semaphore based one.
     printkln!("Running 'async-sem' test");