x86/intel/cacheinfo: Shut up annoying warning

I've been getting the following warning when doing randbuilds
since forever. Now it finally pissed me off just the perfect
amount so that I can fix it.

  arch/x86/kernel/cpu/intel_cacheinfo.c:489:27: warning: ‘cache_disable_0’ defined but not used [-Wunused-variable]
  arch/x86/kernel/cpu/intel_cacheinfo.c:491:27: warning: ‘cache_disable_1’ defined but not used [-Wunused-variable] arch/x86/kernel/cpu/intel_cacheinfo.c:524:27: warning: ‘subcaches’ defined but not used [-Wunused-variable]

It happens because in randconfigs where CONFIG_SYSFS is not set,
the whole sysfs-interface to L3 cache index disabling is
remaining unused and gcc correctly warns about it. Make it
optional, depending on CONFIG_SYSFS too, as is the case with
other sysfs-related machinery in this file.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Link: http://lkml.kernel.org/r/1359969195-27362-1-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/intel_cacheinfo.c

@@ -298,8 +298,7 @@ struct _cache_attr {
 			 unsigned int);
 };
 
-#ifdef CONFIG_AMD_NB
-
+#if defined(CONFIG_AMD_NB) && defined(CONFIG_SYSFS)
 /*
  * L3 cache descriptors
  */
@@ -524,9 +523,9 @@ store_subcaches(struct _cpuid4_info *this_leaf, const char *buf, size_t count,
 static struct _cache_attr subcaches =
 	__ATTR(subcaches, 0644, show_subcaches, store_subcaches);
 
-#else	/* CONFIG_AMD_NB */
+#else
 #define amd_init_l3_cache(x, y)
-#endif /* CONFIG_AMD_NB */
+#endif  /* CONFIG_AMD_NB && CONFIG_SYSFS */
 
 static int
 __cpuinit cpuid4_cache_lookup_regs(int index,