smp, generic: introduce arch_disable_smp_support(), build fix

This function should be provided on UP too.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/smp.h

@@ -66,12 +66,6 @@ extern int __cpu_up(unsigned int cpunum);
  */
 extern void smp_cpus_done(unsigned int max_cpus);
 
-/*
- * Callback to arch code if there's nosmp or maxcpus=0 on the
- * boot command line:
- */
-extern void arch_disable_smp_support(void);
-
 /*
  * Call a function on all other processors
  */
@@ -182,6 +176,12 @@ static inline void init_call_single_data(void)
 #define put_cpu()		preempt_enable()
 #define put_cpu_no_resched()	preempt_enable_no_resched()
 
+/*
+ * Callback to arch code if there's nosmp or maxcpus=0 on the
+ * boot command line:
+ */
+extern void arch_disable_smp_support(void);
+
 void smp_setup_processor_id(void);
 
 #endif /* __LINUX_SMP_H */