x86, voyager: fix smp_intr_init() compile breakage

Impact: fix x86/Voyager build

Looks like this became static on the rest of x86.  Fix it up by adding
an external definition to mach-voyager/setup.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mach-voyager/setup.c b/arch/x86/mach-voyager/setup.c
index 6bbdd63..a580b95 100644
--- a/arch/x86/mach-voyager/setup.c
+++ b/arch/x86/mach-voyager/setup.c
@@ -27,7 +27,7 @@
 void __init intr_init_hook(void)
 {
 #ifdef CONFIG_SMP
-	smp_intr_init();
+	voyager_smp_intr_init();
 #endif
 
 	setup_irq(2, &irq2);