smp: Use smp_call_func_t in on_each_cpu()

Use smp_call_func_t instead of the open coded function pointer argument.

Signed-off-by: Kaitao Cheng <pilgrimtao@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20200417162451.91969-1-pilgrimtao@gmail.com

kernel/smp.c

@@ -620,7 +620,7 @@ void __init smp_init(void)
  * early_boot_irqs_disabled is set.  Use local_irq_save/restore() instead
  * of local_irq_disable/enable().
  */
-void on_each_cpu(void (*func) (void *info), void *info, int wait)
+void on_each_cpu(smp_call_func_t func, void *info, int wait)
 {
 	unsigned long flags;