ACPI: acpi_pad: tune round_robin_time

In an effort to be fair to bound processes,
acpi_pad periodically moves its forced-idle threads.

The default interval for moving the threads is 10 seconds.
Measurements show that reducing this to 1 second has no
power or performance impact, so reduce default to 1 second.

Signed-off-by: Len Brown <len.brown@intel.com>