This patch adds support for tc mqprio offload,
using this different traffic classes on the adapter
can be utilized based on configured priority to tc map.

For example -

tc qdisc add dev eth0 root mqprio num_tc 4 map 0 1 2 3

This will cause SKBs with priority 0,1,2,3 to transmit
over tc 0,1,2,3 hardware queues respectively.
Signed-off-by: Manish Chopra <manish.chopra@cavium.com>
Signed-off-by: Ariel Elior <ariel.elior@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>