mbuf: add fields for tunnels
mbuf: add fields for tunnels

Replace the "reserved2" field with the "packet_type" field
and add the "inner_l2_l3_len" field in the rte_mbuf structure.
The "packet_type" field is used to indicate ordinary packet format and also
tunneling packet format such as IP in IP, IP in GRE, MAC in GRE and MAC in UDP.
The "inner_l2_len" and the "inner_l3_len" fields are added
in the second cache line, they use 2 bytes for TX offloading of tunnels.

Signed-off-by: Jijiang Liu <10b95deab7df654d0c21c8c98b54c9a1ecf2a5c0@intel.com>
Acked-by: Helin Zhang <aba9dfdb1a6ec8bf1ff66b95272c029f8dfde1b1@intel.com>
Tested-by: Yong Liu <d89ea4150d91f674af88bbc382d184dd42ea906c@intel.com>
Acked-by: Thomas Monjalon <ee2fa8b2681c737f775687e475dcbf2028a412f1@6wind.com>

tsphillips/dpdk-fork,tsphillips/dpdk-fork,mixja/dpdk,mixja/dpdk,john-mcnamara-intel/dpdk,msune/dpdk,tsphillips/dpdk-fork,msune/dpdk,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,mixja/dpdk,venkynv/dpdk-mirror,msune/dpdk,john-mcnamara-intel/dpdk,msune/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,mixja/dpdk,venkynv/dpdk-mirror