sched: isolate SMP balancing code a bit more

At the moment, a lot of load balancing code that is irrelevant to non
SMP systems gets included during non SMP builds.

This patch addresses this issue and reduces the binary size on non
SMP systems:

   text    data     bss     dec     hex filename
  10983      28    1192   12203    2fab sched.o.before
  10739      28    1192   11959    2eb7 sched.o.after

Signed-off-by: Peter Williams <pwil3058@bigpond.net.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched_fair.c

@@ -876,6 +876,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
 	}
 }
 
+#ifdef CONFIG_SMP
 /**************************************************
  * Fair scheduling class load-balancing methods:
  */
@@ -1008,6 +1009,7 @@ move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 
 	return 0;
 }
+#endif
 
 /*
  * scheduler tick hitting a task of our scheduling class:
@@ -1084,8 +1086,10 @@ static const struct sched_class fair_sched_class = {
 	.pick_next_task		= pick_next_task_fair,
 	.put_prev_task		= put_prev_task_fair,
 
+#ifdef CONFIG_SMP
 	.load_balance		= load_balance_fair,
 	.move_one_task		= move_one_task_fair,
+#endif
 
 	.set_curr_task          = set_curr_task_fair,
 	.task_tick		= task_tick_fair,