powernow-k8: delay info messages until initialization has succeeded

powernow-k8 is quite prematurely crying Hooray and outputs diagnostic
messages, although the actual initialization can still fail.
Since now we may have acpi-cpufreq already loaded, we move the
messages at the end of the init routine to avoid confusing output
if the loading of powernow-k8 should not succeed.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>