[CPUFREQ] Fix sparse warning in powernow-k8

arch/x86/kernel/cpu/cpufreq/powernow-k8.c:1238:9: warning: symbol '__ptr' shadows an earlier one
arch/x86/kernel/cpu/cpufreq/powernow-k8.c:1238:9: originally declared here
Signed-off-by: Dave Jones <davej@redhat.com>

arch/x86/kernel/cpu/cpufreq/powernow-k8.c

@@ -1234,8 +1234,10 @@ static unsigned int powernowk8_get (unsigned int cpu)
 	struct powernow_k8_data *data;
 	cpumask_t oldmask = current->cpus_allowed;
 	unsigned int khz = 0;
+	unsigned int first;
 
-	data = per_cpu(powernow_data, first_cpu(per_cpu(cpu_core_map, cpu)));
+	first = first_cpu(per_cpu(cpu_core_map, cpu));
+	data = per_cpu(powernow_data, first);
 
 	if (!data)
 		return -EINVAL;