Add return value for pb init function

kernel/sched/pb.c

@@ -25,6 +25,8 @@ int pb_init_rq(struct pb_init_struct *initstr, struct rq *rq)
 	pb->count_admin_cycles = 0;
 
 	pb->is_initialized = 1;	// must be initialized last
+
+	return 0;
 }
 /*
  * Kelvin's Testcodes