net: hns3: remove tc enable checking

Currently, in function hns3_nic_set_real_num_queue(), the
driver doesn't report the queue count and offset for disabled
tc. If user enables multiple TCs, but only maps user
priorities to partial of them, it may cause the queue range
of the unmapped TC being displayed abnormally.

Fix it by removing the tc enable checking, ensure the queue
count is not zero.

With this change, the tc_en is useless now, so remove it.

Fixes: a75a8efa ("net: hns3: Fix tc setup when netdev is first up")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>