To avoid loss when transforming burst to buffer in userspace, send
burst/mtu to kernel directly.

Kernel commit 2e04ad424b("sch_tbf: add TBF_BURST/TBF_PBURST attribute")
make it can handle burst/mtu.

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>