atheros/atlx: use SET_ETHTOOL_OPS directly

As commit a6e28b34("staging/et131x: use SET_ETHTOOL_OPS
directly"), using a wrapper around SET_ETHTOOL_OPS macro is
not actually required, remove and use SET_ETHTOOL_OPS directly.

Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>