x86, nmi: fix build

fix:

arch/x86/kernel/built-in.o: In function `proc_nmi_enabled':
: undefined reference to `nmi_watchdog_default'
arch/x86/kernel/built-in.o: In function `native_smp_prepare_cpus':
: undefined reference to `nmi_watchdog_default'
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/nmi.c

@@ -88,7 +88,6 @@ static inline unsigned int get_timer_irqs(int cpu)
 #endif
 }
 
-#ifdef CONFIG_X86_64
 /* Run after command line and cpu_init init, but before all other checks */
 void nmi_watchdog_default(void)
 {
@@ -96,7 +95,6 @@ void nmi_watchdog_default(void)
 		return;
 	nmi_watchdog = NMI_NONE;
 }
-#endif
 
 #ifdef CONFIG_SMP
 /*