Fix UP compile by having the trivial cpu_online_map

include/linux/smp.h

@@ -86,6 +86,7 @@ extern volatile int smp_msg_id;
 #define smp_call_function(func,info,retry,wait)	({ 0; })
 static inline void smp_send_reschedule(int cpu) { }
 static inline void smp_send_reschedule_all(void) { }
+#define cpu_online_map				1
 #define cpu_online(cpu)				1
 #define num_online_cpus()			1
 #define __per_cpu_data