examples/l3fwd-power: support traffic pattern aware control

examples/l3fwd-power: support traffic pattern aware control

Add the support for new traffic pattern aware power control
power management API.

Example:
./l3fwd-power -l xxx   -n 4   -w 0000:xx:00.0 -w 0000:xx:00.1 -- -p 0x3
-P --config="(0,0,xx),(1,0,xx)" --empty-poll="0,0,0" -l 14 -m 9 -h 1

Please Reference l3fwd-power document for full parameter usage

The option "l", "m", "h" are used to set the power index for
LOW, MED, HIGH power state. Only is useful after enable empty-poll

--empty-poll="training_flag, med_threshold, high_threshold"

The option training_flag is used to enable/disable training mode.

The option med_threshold is used to indicate the empty poll threshold
of modest state which is customized by user.

The option high_threshold is used to indicate the empty poll threshold
of busy state which is customized by user.

Above three option default value is all 0.

Once enable empty-poll. System will apply the default parameter if no
other command line options are provided.

If training mode is enabled, the user should ensure that no traffic
is allowed to pass through the system. When training phase complete,
the application transfer to normal operation

System will start running with the modest power mode.
If the traffic goes above 70%, then system will move to High power state.
If the traffic drops below 30%, the system will fallback to the modest
power state.

Example code use master thread to monitoring worker thread busyness.
The default timer resolution is 10ms.

Signed-off-by: Liang Ma <liang.j.ma@intel.com>
Reviewed-by: Lei Yao <lei.a.yao@intel.com>
Acked-by: David Hunt <david.hunt@intel.com>