tc: mqprio: reject queues count/offset pair count higher than num_tc

tc: mqprio: reject queues count/offset pair count higher than num_tc

Provide a sanity check that will make sure whether queues count/offset
pair count will not exceed the actual number of TCs being created.

Example command that is invalid because there are 4 count/offset pairs
whereas num_tc is only 2.

 # tc qdisc add dev enp96s0f0 root mqprio num_tc 2 map 0 0 0 0 1 1 1 1
queues 4@0 4@4 4@8 4@12 hw 1 mode channel

Store the parsed count/offset pair count onto a dedicated variable that
will be compared against opt.num_tc after all of the command line
arguments were parsed. Bail out if this count is higher than opt.num_tc
and let user know about it.

Drivers were swallowing such commands as they were iterating over
count/offset pairs where num_tc was used as a delimiter, so this is not
a big deal, but better catch such misconfiguration at the command line
argument parsing level.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: David Ahern <dsahern@gmail.com>