softirqs: Make wakeup_softirqd static

No users outside of kernel/softirq.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 07b4f1b..80f6e3b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -67,7 +67,7 @@
  * to the pending events, so lets the scheduler to balance
  * the softirq load for us.
  */
-void wakeup_softirqd(void)
+static void wakeup_softirqd(void)
 {
 	/* Interrupts are disabled: no need to stop preemption */
 	struct task_struct *tsk = __get_cpu_var(ksoftirqd);