examples/ip_pipeline: add load balancing to pass-through

examples/ip_pipeline: add load balancing to pass-through

The pass-through pipeline implementation is extended with load balancing
function. This function allows uniform distribution of the packets among
its output ports. For packets distribution, any application level logic
can be applied. For instance, in this implementation, hash value
computed over specific header fields of the incoming packets has been
used to spread traffic uniformly among the output ports.

The following pass-through configuration can be used for implementing
load balancing function over ipv4 traffic;

[PIPELINE0]
type = PASS-THROUGH
core = 0
pktq_in = RXQ0.0 RXQ1.0 RXQ2.0 RXQ3.0
pktq_out = TXQ0.0 TXQ1.0 TXQ2.0 TXQ3.0
dma_src_offset = 278; mbuf (128) + headroom (128) + 1st ethertype offset (14) + ttl offset within ip header = 278 (ipv4)
dma_dst_offset = 128; mbuf (128)
dma_size = 16
dma_src_mask = 00FF0000FFFFFFFFFFFFFFFFFFFFFFFF
dma_hash_offset = 144; (dma_dst_offset+dma_size)
lb = hash

Signed-off-by: Jasvinder Singh <jasvinder.singh@intel.com>
Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>