x86: fix compiling with 64bit with def_to_bigsmp

only need to do cut off with 32bit
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/smpboot.c

@@ -1000,7 +1000,7 @@ static int __init smp_sanity_check(unsigned max_cpus)
 {
 	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;