net: hns3: fix a bug in hns3_driv_to_eth_caps

The value of link_modes.advertising and the value of link_modes.supported
is initialized to zero every time in for loop in hns3_driv_to_eth_caps().
But we just want to set specified bit for them. Initialization is
unnecessary. This patch fixes it.

Fixes: 496d03e9 (net: hns3: Add Ethtool support to HNS3 driver)
Signed-off-by: Fuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: Lipeng <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>