[PATCH] oprofile needs smp_num_siblings on x86-64

P4 oprofile needs cpu_sibling_map and smp_num_siblings, the later
was not exported

arch/x86_64/kernel/x8664_ksyms.c

@@ -196,6 +196,7 @@ EXPORT_SYMBOL(die_chain);
 
 #ifdef CONFIG_SMP
 EXPORT_SYMBOL(cpu_sibling_map);
+EXPORT_SYMBOL(smp_num_siblings);
 #endif
 
 extern void do_softirq_thunk(void);