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

mainline inclusion
from mainline-master
commit d59daf6a
category: feature
bugzilla: 173966
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d59daf6a4ceedf342f349e94f1300e1598213252



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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>
Reviewed-by: Yongxin Li <liyongxin1@huawei.com>
Signed-off-by: Junxin Chen <chenjunxin1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>