x86: fix compiling with 64bit with def_to_bigsmp

only need to do cut off with 32bit

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2912fa3..4c3cff5 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1000,7 +1000,7 @@
 {
 	preempt_disable();
 
-#ifndef CONFIG_X86_BIGSMP
+#if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
 	if (def_to_bigsmp && nr_cpu_ids > 8) {
 		unsigned int cpu;
 		unsigned nr;