perf_counter, x86: declare perf_max_counters only for CONFIG_PERF_COUNTERS

This is only needed for CONFIG_PERF_COUNTERS enabled.

[ Impact: cleanup ]
Signed-off-by: Robert Richter <robert.richter@amd.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1241002046-8832-3-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/perf_counter.h

@@ -512,12 +512,13 @@ struct perf_cpu_context {
 	int			recursion[4];
 };
 
+#ifdef CONFIG_PERF_COUNTERS
+
 /*
  * Set by architecture code:
  */
 extern int perf_max_counters;
 
-#ifdef CONFIG_PERF_COUNTERS
 extern const struct hw_perf_counter_ops *
 hw_perf_counter_init(struct perf_counter *counter);