net: hns3: add support for 1us unit GL configuration

For device whose version is above V3(include V3), the GL
configuration can set as 1us unit, so adds support for
configuring this field.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>