net: hns3: add support for dumping MAC umv counter in debugfs

mainline inclusion
from mainline-v5.14-rc1
commit d59daf6a
category: feature
bugzilla: NA
CVE: NA

----------------------------

This patch adds support of dumping MAC umv counter in debugfs,
which will be helpful for debugging.

The display style is below:
$ cat umv_info
num_alloc_vport  : 2
max_umv_size     : 256
wanted_umv_size  : 256
priv_umv_size    : 85
share_umv_size   : 86
vport(0) used_umv_num : 1
vport(1) used_umv_num : 1

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>
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Reviewed-by: Junxin Chen <chenjunxin1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>