perf_counter: Remove unused variables

Fix a gcc unused variables warning.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 7e346d4..a7aa8f9 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -1570,8 +1570,6 @@
 
 static int p6_pmu_init(void)
 {
-	int high, low;
-
 	switch (boot_cpu_data.x86_model) {
 	case 1:
 	case 3:  /* Pentium Pro */