As the user manual described, the second step to write to C45 phy
by mdio should be data, but not address. Here we should fix this
issue.

Fixes: 5b904d39 ("net: add Hisilicon Network Subsystem MDIO support")
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Reviewed-by: Nlipeng <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>