net: hns3: fix wrong judgment condition issue

In hns3_dcbnl_ieee_delapp, should check ieee_delapp not ieee_setapp.
This path fix the wrong judgment.

Fixes: 0ba22bcb

 ("net: hns3: add support config dscp map to tc")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>