net: hns3: fix get VF RSS issue

For revision 0x20, VF shares the same RSS config with PF.
In original codes, it always return 0 when query RSS hash
key for VF. This patch fixes it by return the hash key
got from PF.

Fixes: 374ad291

 ("net: hns3: net: hns3: Add RSS general configuration support for VF")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>