net: hns3: refactor dump qos pause cfg of debugfs

mainline inclusion
from mainline-v5.14-rc1
commit 6571ec2e
category: feature
bugzilla: NA
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6571ec2eda65



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Currently, user gets pause config by implementing debugfs command
"echo dump qos pause cfg > cmd", this command will dump info in dmesg.
It's unnecessary and heavy.

To optimize it, create a single file "qos_pause_cfg" in tm directory
and use cat command to get info. It will return info to userspace,
rather than record in dmesg.

The display style is below:
$ cat qos_pause_cfg
pause_trans_gap: 0x7f
pause_trans_time: 0xffff

Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@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>