sys: Remove $FreeBSD$: one-line bare tag

Remove /^\s*\$FreeBSD\$$\n/

e1000: Update copyrights and readme

Copyrights in sync with "cid-gigabit.2020.06.05.tar.gz released by ND"
(from DPDK).

README from the latest em-7.7.8 on intel.com

Approved by: imp
MFC after: 1 week

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

MFC of the em/igb drivers

Update the 1G drivers, shared code sync with Intel,
igb now has a queue notion that has a single interrupt
with an RX/TX pair, this will reduce the total interrupts
seen on a system. Both em and igb have a new watchdog
method. igb has fixes from Pyun Yong-Hyeon that have
improved stability, thank you :)

I wish to MFC this for 7.3 asap, please test if able.

Resync with Intel versions of both the em and igb
drivers. These add new hardware support, most importantly
the pch (i5 chipset) in the em driver. Also, both drivers
now have the simplified (and I hope improved) watchdog
code. The igb driver uses the new RX cleanup that I
first implemented in ixgbe.

em - version 6.9.24
igb - version 1.8.4

- Import the HEAD csup code which is the basis for the cvsmode work.

Merge of the source for igb and em into dev/e1000, this
proved to be necessary to make the static drivers work
in EITHER/OR or BOTH configurations. Modules will still
build in sys/modules/igb or em as before.

This also updates the igb driver for support for the 82576
adapter, adds shared code fixes, and etc....

MFC after: ASAP