ixgbe: Clear stale pool mappings

This patch makes certain that we clear the pool mappings added when we
configure default MAC addresses for the interface.  Without this we run the
risk of leaking an address into pool 0 which really belongs to VF 0 when
SR-IOV is enabled.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>