e1000: Update intel shared code

Sync the e1000 shared code with DPDK shared code
"cid-gigabit.2020.06.05.tar.gz released by ND"

Primary focus was on client platforms (ich8lan). More work remains here
but we need an Intel contact for client networking.

Reviewed by: grehan, Intel Networking (erj, earlier rev)
Obtained from: DPDK http://git.dpdk.org/dpdk/tree/drivers/net/e1000/base
MFC after: 1 week
Sponsored by: me
Differential Revision: https://reviews.freebsd.org/D31547