acpi: fix printk format warning

Fix printk format warning:

linux-next-20080617/drivers/acpi/processor_throttling.c:1258: warning: format '%d' expects type 'int', but argument 4 has type 'size_t'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>