net: hns3: Add "dcb register" status information query function

This patch prints dcb register status  information by module.

debugfs command:
root@(none)# echo dump reg dcb > cmd
 roce_qset_mask: 0x0
 nic_qs_mask: 0x0
 qs_shaping_pass: 0x0
 qs_bp_sts: 0x0
 pri_mask: 0x0
 pri_cshaping_pass: 0x0
 pri_pshaping_pass: 0x0
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>