net: hns3: fix "tc qdisc del" failed issue

net: hns3: fix "tc qdisc del" failed issue

[ Upstream commit 5eb01ddfcfb25e6ebc404a41deae946bde776731 ]

The HNS3 driver supports to configure TC numbers and TC to priority
map via "tc" tool. But when delete the rule, will fail, because
the HNS3 driver needs at least one TC, but the "tc" tool sets TC
number to zero when delete.

This patch makes sure that the TC number is at least one.

Fixes: 30d240dfa2e8 ("net: hns3: Add mqprio hardware offload support in hns3 driver")
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>