This patch limits some variables' scope as much as possible in
hns3_fill_desc.

Also, only set l3_type and l4_type when necessary.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NHuazhong tan <tanhuazhong@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>