mutex: removed docstring comment that is no longer relevant

src/core/hle/kernel/mutex.h

@@ -19,7 +19,6 @@ Result ReleaseMutex(Handle handle);
 
 /**
  * Creates a mutex
- * @param handle Reference to handle for the newly created mutex
  * @param initial_locked Specifies if the mutex should be locked initially
  * @return Handle to newly created object
  */