Create a blacklist for processors that should not load the acpi-cpufreq module.

The initial entry in the blacklist function is the Intel 0f68 processor.  It's
specification update mentions errata AL30 which implies that cpufreq should not
run on this processor.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Dave Jones <davej@redhat.com>