net: hns3: fix a typo in struct hclge_mac

The member link of struct hclge_mac stores the link status of
MAC and PHY if PHY exists, but its annotation uses word "exit",
so fix it.

Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>