net: hns3: Add "manager table" information query function

This patch prints manager table information.

debugfs command:
echo dump mng tbl > cmd

Sample Command:
root@(none)# echo dump mng tbl > cmd
 entry|mac_addr         |mask|ether|mask|vlan|mask|i_map|i_dir|e_type
 00   |01:00:5e:00:00:01|0   |00000|0   |0000|0   |00   |00   |0
 01   |c2:f1:c5:82:68:17|0   |00000|0   |0000|0   |00   |00   |0
root@(none)#

Signed-off-by: liuzhongzhu <liuzhongzhu@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>