[CPUFREQ] Handle CPUs with different capabilities in acpi-cpufreq

acpi-cpufreq checks each CPU for aperf/mperf support, but only sets a
global flag. This will cause errors if some CPUs in the system don't
support the feature. Check boot_cpu_has() instead in order to make sure
that all CPUs support it.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Dave Jones <davej@redhat.com>