Added a new irq_control system call

This is currently an empty call. It will be used for registering,
receiving and releasing irqs.

src/api/SConscript

@@ -3,7 +3,7 @@ Import('env')
 Import('symbols')
 
 # The set of source files associated with this SConscript file.
-src_local = ['kip.c', 'syscall.c', 'thread.c', 'ipc.c', 'map.c', 'mutex.c', 'cap.c', 'exregs.c']
+src_local = ['kip.c', 'syscall.c', 'thread.c', 'ipc.c', 'map.c', 'mutex.c', 'cap.c', 'exregs.c', 'irq.c']
 
 obj = env.Object(src_local)
 

src/api/syscall.c

@@ -36,11 +36,6 @@ int sys_schedule(void)
 	return 0;
 }
 
-int sys_space_control(void)
-{
-	return -ENOSYS;
-}
-
 int sys_getid(struct task_ids *ids)
 {
 	struct ktcb *this = current;