x86/mce/AMD: Fix UP build error

141168c36c ("x86: Simplify code by removing a !SMP #ifdefs
from 'struct cpuinfo_x86'") removed a bunch of CONFIG_SMP ifdefs
around code touching struct cpuinfo_x86 members but also caused
the following build error with Randy's randconfigs:

mce_amd.c:(.cpuinit.text+0x4723): undefined reference to `cpu_llc_shared_map'

Restore the #ifdef in threshold_create_bank() which creates
symlinks on the non-BSP CPUs.

There's a better patch series being worked on by Kevin Winchester
which will solve this in a cleaner fashion, but that series is
too ambitious for v3.3 merging - so we first queue up this trivial
fix and then do the rest for v3.4.

Signed-off-by: Borislav Petkov <bp@alien8.de>
Acked-by: Kevin Winchester <kjwinchester@gmail.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Nick Bowler <nbowler@elliptictech.com>
Link: http://lkml.kernel.org/r/20120203191801.GA2846@x1.osrc.amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/cpu/mcheck/mce_amd.c

@@ -528,6 +528,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
 
 	sprintf(name, "threshold_bank%i", bank);
 
+#ifdef CONFIG_SMP
 	if (cpu_data(cpu).cpu_core_id && shared_bank[bank]) {	/* symlink */
 		i = cpumask_first(cpu_llc_shared_mask(cpu));
 
@@ -553,6 +554,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
 
 		goto out;
 	}
+#endif
 
 	b = kzalloc(sizeof(struct threshold_bank), GFP_KERNEL);
 	if (!b) {