Filters cleanup should be done once before destroying net device,
since filters list is contained in the private data.

Fixes: 1eb8c695 ('net/mlx4_en: Add accelerated RFS support')
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>