igb: Add register defines needed for time sync functions

This patch adds defines needed for implementing the auxiliary time sync
functions and also changes code to call the updated defines instead of
the old.

Reported-by: Richard Cochran <ricahrdcochran@gmail.com>
Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>