igb: drop the "adv" off function names relating to descriptors

Many of the function names in the hot path are carrying an extra "_adv"
suffix on the end of them to represent the fact that they are using
advanced descriptors instead of legacy descriptors.  However since all igb
uses are advanced descriptors adding the extra suffix doesn't really add
any additional data.  Since this is the case it is easiest to just drop the
suffix and save us from having to store the extra characters.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>