On larger systems intel_pstate currently spams the boot up
log with its "Intel pstate controlling ..." message for each CPU.
It's the only subsystem that prints a message for each
CPU.
Turn the message into a pr_debug.
Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>