[CPUFREQ] acpi-cpufreq: add missing __percpu markup

acpi_perf_data is a percpu pointer but was missing __percpu markup.
Add it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>

arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

@@ -72,7 +72,7 @@ struct acpi_cpufreq_data {
 static DEFINE_PER_CPU(struct acpi_cpufreq_data *, acfreq_data);
 
 /* acpi_perf_data is a pointer to percpu data. */
-static struct acpi_processor_performance *acpi_perf_data;
+static struct acpi_processor_performance __percpu *acpi_perf_data;
 
 static struct cpufreq_driver acpi_cpufreq_driver;