This patch registers callbacks to support HTB offload.

Below are features supported,

- supports traffic shaping on the given class by honoring rate and ceil
configuration.

- supports traffic scheduling,  which prioritizes different types of
traffic based on strict priority values.

- supports the creation of leaf to inner classes such that parent node
rate limits apply to all child nodes.
Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com>
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>