net/mlx4_en: use napi_complete_done() return value
Do not rearm interrupts if we are busy polling.
mlx4 uses separate CQ for TX and RX, so number of TX interrupts
does not change, unfortunately.
Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Adam Belay <abelay@google.com> Cc: Tariq Toukan <tariqt@mellanox.com> Cc: Yuval Mintz <Yuval.Mintz@cavium.com> Cc: Ariel Elior <ariel.elior@cavium.com> Signed-off-by: David S. Miller <davem@davemloft.net>