Remove spinlock syscalls

Author: mkroening

src/syscalls/mod.rs

@@ -10,7 +10,6 @@ pub use self::futex::*;
 pub use self::processor::*;
 pub use self::recmutex::*;
 pub use self::semaphore::*;
-pub use self::spinlock::*;
 pub use self::system::*;
 pub use self::tasks::*;
 pub use self::timer::*;
@@ -32,7 +31,6 @@ pub mod net;
 mod processor;
 mod recmutex;
 mod semaphore;
-mod spinlock;
 mod system;
 mod tasks;
 mod timer;