[CPUFREQ] Fix powernow-k8 SMP kernel on UP hardware bug.

Fix powernow-k8 doesn't load bug.
Reference:
https://launchpad.net/distros/ubuntu/+source/linux-source-2.6.15/+bug/35145



Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Signed-off-by: Dave Jones <davej@redhat.com>