Removed lifetime tag from Semaphore implementation

src/kernel/synch.rs

@@ -18,7 +18,7 @@ pub struct Semaphore {
 
 }
 
-impl<'t> Semaphore {
+impl Semaphore {
 
     ///     Decrement the value, and wait if it becomes < 0. Checking the
     ///	value and decrementing must be done atomically, so we