commit d253d2a526 (Improve accuracy by not truncating until final
result), changed internal variables of the PID to be fixed point
numbers. Update the pid_reset() to reflect this change.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>