tick: Remove arch_needs_cpu

Remove unused arch_needs_cpu() hook. No architectures use it after
s390 removed its use case.

Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

include/linux/tick.h

@@ -44,9 +44,6 @@ static inline void tick_unfreeze(void) { }
 
 #ifdef CONFIG_TICK_ONESHOT
 extern void tick_irq_enter(void);
-#  ifndef arch_needs_cpu
-#   define arch_needs_cpu() (0)
-#  endif
 # else
 static inline void tick_irq_enter(void) { }
 #endif

kernel/time/tick-sched.c

@@ -828,8 +828,7 @@ static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
 	ts->timer_expires_base = basemono;
 
 	/*
-	 * Keep the periodic tick, when RCU, architecture or irq_work
-	 * requests it.
+	 * Keep the periodic tick, when RCU or irq_work requests it.
 	 * Aside of that, check whether the local timer softirq is
 	 * pending. If so, its a bad idea to call get_next_timer_interrupt(),
 	 * because there is an already expired timer, so it will request
@@ -837,8 +836,8 @@ static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
 	 * minimal delta, which brings us back to this place
 	 * immediately. Lather, rinse and repeat...
 	 */
-	if (rcu_needs_cpu() || arch_needs_cpu() ||
-	    irq_work_needs_cpu() || local_timer_softirq_pending()) {
+	if (rcu_needs_cpu() || irq_work_needs_cpu() ||
+	    local_timer_softirq_pending()) {
 		next_tick = basemono + TICK_NSEC;
 	} else {
 		/*