x86: Add cpu_has_topoext

Introduce cpu_has_topoext to check for AMD's CPUID topology extensions
support. It indicates support for
CPUID Fn8000_001D_EAX_x[N:0]-CPUID Fn8000_001E_EDX

See AMD's CPUID Specification, Publication # 25481
(as of Rev. 2.34 September 2010)

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Link: http://lkml.kernel.org/r/20121019085813.GD26718@alberich
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 8c297aa..c22a492 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -311,6 +311,7 @@
 #define cpu_has_cx8		boot_cpu_has(X86_FEATURE_CX8)
 #define cpu_has_cx16		boot_cpu_has(X86_FEATURE_CX16)
 #define cpu_has_eager_fpu	boot_cpu_has(X86_FEATURE_EAGER_FPU)
+#define cpu_has_topoext		boot_cpu_has(X86_FEATURE_TOPOEXT)
 
 #if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64)
 # define cpu_has_invlpg		1