net: hns: Correct HNS RSS key set function

This patch fixes below ethtool configuration error:

localhost:~ # ethtool -X eth0 hkey XX:XX:XX...
Cannot set Rx flow hash configuration: Operation not supported

Signed-off-by: lipeng <lipeng321@huawei.com>
Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>