x86: build fix

fix:

arch/x86/kernel/setup_32.c:409: error: 'enable_local_apic' undeclared (first use in this function)
arch/x86/kernel/setup_32.c:409: error: (Each undeclared identifier is reported only once
arch/x86/kernel/setup_32.c:409: error: for each function it appears in.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/setup_32.c

@@ -406,7 +406,9 @@ void __init setup_arch(char **cmdline_p)
 	parse_early_param();
 
 	if (acpi_mps_check()){
+#ifdef CONFIG_X86_LOCAL_APIC
 		enable_local_apic = -1;
+#endif
 		clear_cpu_cap(&boot_cpu_data, X86_FEATURE_APIC);
 	}