x86, amd: Enable L3 cache index disable on family 0x15

AMD family 0x15 CPUs support L3 cache index disable, so enable
it on them.
Signed-off-by: NHans Rosenfeld <hans.rosenfeld@amd.com>
Cc: <andreas.herrmann3@amd.com>
LKML-Reference: <1295881543-572552-3-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/amd_nb.c

@@ -85,6 +85,9 @@ int amd_cache_northbridges(void)
 	     boot_cpu_data.x86_mask >= 0x1))
 		amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
 
+	if (boot_cpu_data.x86 == 0x15)
+		amd_northbridges.flags |= AMD_NB_L3_INDEX_DISABLE;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(amd_cache_northbridges);