iflib: Introduce v2 of TX Queue Select Functionality

For v2, iflib will parse packet headers before queueing a packet.

This commit also adds a new field in the structure that holds parsed
header information from packets; it stores the IP ToS/traffic class
field found in the IPv4/IPv6 header.

To help, it will only partially parse header packets before queueing
them by using a new header parsing function that does less than the
current parsing header function; for our purposes we only need up to the
minimal IP header in order to get the IP ToS infromation and don't need
to pull up more data.

For now, v1 and v2 co-exist in this patch; v1 still offers a
less-invasive method where none of the packet is parsed in iflib before
queueing.

This also bumps the sys/param.h version.

Signed-off-by: Eric Joyner <erj@FreeBSD.org>
Tested by: IntelNetworking
MFC after: 3 days
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D34742