net: hns: remove unnecessary !! operation in hns_mac_config_sds_loopback_acpi()

The !! operation of variable en in hns_mac_config_sds_loopback_acpi()
is redundant, so remove it.

Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>