kernel: Fix style issues

src/system/kernel/scheduler/scheduler_simple.cpp

@@ -290,7 +290,7 @@ simple_estimate_max_scheduling_latency(Thread* thread)
 
 
 static int32
-reschedule_event(timer *unused)
+reschedule_event(timer* /* unused */)
 {
 	// This function is called as a result of the timer event set by the
 	// scheduler. Make sure the reschedule() is invoked.