ixgbe: add support for X550 source_address_prunning

This patch will enable X550 Source Address Prunning for VEPA
bridge mode.  This requires that we also have replication enabled
as well, while in this mode.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>