cpufreq: speedstep-smi: fix decimal printf specifiers

The prefix suggests the number should be printed in hex, so use
the %x specifier to do that. Also, these are 32-bit values,
so drop the l characters.

Signed-off-by: Hans Wennborg <hans@hanshq.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>