mbuf: add definitions of unified packet types

mbuf: add definitions of unified packet types

As there are only 6 bit flags in ol_flags for indicating packet
types, which is not enough to describe all the possible packet
types hardware can recognize. For example, i40e hardware can
recognize more than 150 packet types. Unified packet type is
composed of L2 type, L3 type, L4 type, tunnel type, inner L2 type,
inner L3 type and inner L4 type fields, and can be stored in
'struct rte_mbuf' of 32 bits field 'packet_type'.

To avoid breaking ABI compatibility, all the changes would be
enabled by RTE_NEXT_ABI.

Signed-off-by: Helin Zhang <helin.zhang@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>