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

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

I thank all developers and contributors for pc98.

Relnotes:	yes

implemented with macros. This patch improves code readability. Reasoning
behind vidd_* is a sort of "video discipline".

List of macros is supposed to be complete--all methods of video_switch
ought to have their respective macros from now on.

Functionally, this code should be no-op. My intention is to leave current
behaviour of touched code as is.

No objections:	rwatson
Silence on:	freebsd-current@
Approved by:	cognet

  table on the pc98 console.
- Remove old epson note support.

Obtained from:	FreeBSD(98) 4.0R-Rev01

- Split terminal emulation code from the main part of the driver so
that we can have alternative terminal emulator modules if we like in
the future.  (We are not quite there yet, though.)

- Put sysmouse related code in a separate file, thus, simplifying the
main part of the driver.

As some files are added to the source tree, you need to run config(8)
before you compile a new kernel next time.

You shouldn't see any functional change by this commit; this is only
internal code reorganization.