x86: io_apic.c io_apic_sync should be static

Impact: cleanup, reduce kernel size a bit, avoid sparse warning

Fixes sparse warning:

  arch/x86/kernel/io_apic.c:709:6: warning: symbol 'io_apic_sync' was not declared. Should it be static?

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index 679e7bb..b8c8a8e 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -481,7 +481,7 @@
 }
 
 #ifdef CONFIG_X86_64
-void io_apic_sync(struct irq_pin_list *entry)
+static void io_apic_sync(struct irq_pin_list *entry)
 {
 	/*
 	 * Synchronize the IO-APIC and the CPU by doing