x86: move prefill_possible_map calling early, fix, V2

Commit 4a701737 ("x86: move prefill_possible_map calling early, fix")
is the wrong fix: prefill_possible_map() needs to be available
even when CONFIG_HOTPLUG_CPU is not set. A followon patch will do that.

Fix this correctly by making prefill_possible_map() available even when
CONFIG_HOTPLUG_CPU is not set. The function is needed so that
the number of possible CPUs can be determined.

Tested on uniprocessor machine with CPU hotplug disabled.

From boot log:
  Before: NR_CPUS: 512, nr_cpu_ids: 512, nr_node_ids 1
  After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1

Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/smp.h b/include/asm-x86/smp.h
index 6df2615..a6afc29 100644
--- a/include/asm-x86/smp.h
+++ b/include/asm-x86/smp.h
@@ -141,6 +141,8 @@
 void native_send_call_func_ipi(cpumask_t mask);
 void native_send_call_func_single_ipi(int cpu);
 
+extern void prefill_possible_map(void);
+
 void smp_store_cpu_info(int id);
 #define cpu_physical_id(cpu)	per_cpu(x86_cpu_to_apicid, cpu)
 
@@ -149,15 +151,11 @@
 {
 	return cpus_weight(cpu_callout_map);
 }
-#endif /* CONFIG_SMP */
-
-#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_CPU)
-extern void prefill_possible_map(void);
 #else
 static inline void prefill_possible_map(void)
 {
 }
-#endif
+#endif /* CONFIG_SMP */
 
 extern unsigned disabled_cpus __cpuinitdata;