ixgbe: use NETIF_F_LRO

Both ETH_FLAG_LRO and NETIF_F_LRO have the same value, but NETIF_F_LRO
is intended to use with netdev->features.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>