net: hns3: add ethtool -p support for fiber port

Add led location support for fiber port. The led will keep blinking
when locating.

Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>