sched/nohz: Merge CONFIG_NO_HZ_COMMON blocks

Now that we have two back-to-back NO_HZ_COMMON blocks, merge them.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

kernel/sched/fair.c

@@ -9487,11 +9487,7 @@ void nohz_balance_enter_idle(int cpu)
 	 */
 	WRITE_ONCE(nohz.has_blocked, 1);
 }
-#else
-static inline void nohz_balancer_kick(struct rq *rq) { }
-#endif
 
-#ifdef CONFIG_NO_HZ_COMMON
 /*
  * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
  * rebalancing for all the CPUs for whom scheduler ticks are stopped.
@@ -9598,12 +9594,14 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
 
 	return true;
 }
-#else
+#else /* !CONFIG_NO_HZ_COMMON */
+static inline void nohz_balancer_kick(struct rq *rq) { }
+
 static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
 {
 	return false;
 }
-#endif
+#endif /* CONFIG_NO_HZ_COMMON */
 
 /*
  * run_rebalance_domains is triggered when needed from the scheduler tick.