x86: use cpuid vector 0xb when available for detecting cpu topology

cpuid leaf 0xb provides extended topology enumeration. This interface provides
the 32-bit x2APIC id of the logical processor and it also provides a new
mechanism to detect SMT and core siblings (which provides increased
addressability).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 5f58da4..79338fe 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -161,6 +161,7 @@
 extern unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c);
 extern unsigned short num_cache_leaves;
 
+extern void detect_extended_topology(struct cpuinfo_x86 *c);
 #if defined(CONFIG_X86_HT) || defined(CONFIG_X86_64)
 extern void detect_ht(struct cpuinfo_x86 *c);
 #else