Add mqprio qdisc support. Output matches the following,

qdisc mq 0: dev eth1 root
qdisc mq 0: dev eth2 root
qdisc mqprio 8001: dev eth3 root  tc 8 map 0 1 2 3 4 5 6 7 1 1 1 1 1 1 1 1
             queues:(0:7) (8:15) (16:23) (24:31) (32:39) (40:47) (48:55) (56:63)

And usage is,

Usage: ... mclass [num_tc NUMBER] [map P0 P1...]
                  [offset txq0 txq1 ...] [count cnt0 cnt1 ...] [hw 1|0]
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>