AUTHORS: Move src/cpu/intel copyrights into AUTHORS file

As discussed on the mailing list and voted upon, the coreboot project
is going to move the majority of copyrights out of the headers and into
an AUTHORS file.  This will happen a bit at a time, as we'll be unifying
license headers at the same time.

Signed-off-by: Martin Roth <martin@coreboot.org>
Change-Id: I39f52764dc377c25953ef5dba16982a0b4637cdb
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35181
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Guckian
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/cpu/intel/speedstep/acpi.c

@@ -1,9 +1,6 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright (C) 2009 coresystems GmbH
- *               2012 secunet Security Networks AG
- *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; version 2 of

src/cpu/intel/speedstep/speedstep.c

@@ -1,8 +1,6 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright (C) 2012 secunet Security Networks AG
- *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; version 2 of