net: hns3: remove back in struct hclge_hw

hclge_hw is embedded in hclge_dev, so use container_of instead of
back to get hclge_dev.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>