sched/deadline: Introduce start_hrtick_dl() for !CONFIG_SCHED_HRTICK

Introduce start_hrtick_dl for !CONFIG_SCHED_HRTICK to align with
the fair class.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Kirill Tkhai <ktkhai@parallels.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1415670747-58726-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/deadline.c

@@ -1013,6 +1013,10 @@ static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
 {
 	hrtick_start(rq, p->dl.runtime);
 }
+#else /* !CONFIG_SCHED_HRTICK */
+static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
+{
+}
 #endif
 
 static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,
@@ -1066,10 +1070,8 @@ struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev)
 	/* Running task will never be pushed. */
        dequeue_pushable_dl_task(rq, p);
 
-#ifdef CONFIG_SCHED_HRTICK
 	if (hrtick_enabled(rq))
 		start_hrtick_dl(rq, p);
-#endif
 
 	set_post_schedule(rq);
 
@@ -1088,10 +1090,8 @@ static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
 {
 	update_curr_dl(rq);
 
-#ifdef CONFIG_SCHED_HRTICK
 	if (hrtick_enabled(rq) && queued && p->dl.runtime > 0)
 		start_hrtick_dl(rq, p);
-#endif
 }
 
 static void task_fork_dl(struct task_struct *p)