bond: add mode 5

bond: add mode 5

Add support for mode 5 (Transmit load balancing) into pmd driver

This patch add support for Adaptive transmit load balancing (mode 5) to the
librte_pmd_bond library. This mode provides an adaptive transmit load
balancing. It dynamically changes the transmitting slave, according to the
computed load.

Further details are described here:
https://www.kernel.org/doc/Documentation/networking/bonding.txt
In implementation callback is used for sorting slave order - providing
statistics for burst function about slave bandwith usage  and sort
interfaces due to usage.

Difference in this implementation vs Linux implementation:
- We Are trying send all pkts – If one interface hasn’t send packets we are
trying to send rest of packets by other slaves sorted previously by callback
function.

Some implementation details:
- Every 100ms is taken obytes statistics from every slave.
- Every 10 ms the slaves in  table are sorted and updated by callback -
bandwidth and successfully transmitted bytes from previous iteration which
happens every 100 ms
- There is callback function which updates this statistics for transparency and
for rather intensive computation involved in this mode.

Test report: http://dpdk.org/ml/archives/dev/2014-November/008729.html

Signed-off-by: Daniel Mrzyglod <danielx.t.mrzyglod@intel.com>
Tested-by: SunX Jiajia <sunx.jiajia@intel.com>
Acked-by: Declan Doherty <declan.doherty@intel.com>