net: hns3: Rename loop mode

Our loop mode includes mac loop, serdes loop and phy loop. Not all of them
are related with mac. This patch corrects their names.

Signed-off-by: Fuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>