Currently, when query PFC configuration by dcbtool, driver will return
PFC enable status based on TC. As all priorities are mapped to TC0 by
default, if TC0 is enabled, then all priorities mapped to TC0 will be
shown as enabled status when query PFC setting, even though some
priorities have never been set.

for example:
$ dcb pfc show dev eth0
pfc-cap 4 macsec-bypass off delay 0
prio-pfc 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
$ dcb pfc set dev eth0 prio-pfc 0:on 1:on 2:on 3:on
$ dcb pfc show dev eth0
pfc-cap 4 macsec-bypass off delay 0
prio-pfc 0:on 1:on 2:on 3:on 4:on 5:on 6:on 7:on

To fix this problem, just returns user's PFC config parameter saved in
driver.

Fixes: cacde272 ("net: hns3: Add hclge_dcb module for the support of DCB feature")
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>