net: hns3: add support for querying maximum value of GL

mainline inclusion
from mainline-v5.11-rc1
commit ab16b49c
category: feature
bugzilla: 173966
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab16b49cdf986172373afc16b4039f058aa3b22d



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For maintainability and compatibility, add support for querying
the maximum value of GL.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: li yongxin <liyongxin1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>