AUTHORS: Move src/cpu 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: Id6070fb586896653a1e44951a6af8f42f93b5a7b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35184
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/cpu/x86/mtrr/mtrr.c b/src/cpu/x86/mtrr/mtrr.c
index 98449d5..b26e31a 100644
--- a/src/cpu/x86/mtrr/mtrr.c
+++ b/src/cpu/x86/mtrr/mtrr.c
@@ -1,10 +1,5 @@
 /*
- * mtrr.c: setting MTRR to decent values for cache initialization on P6
- *
- * Derived from intel_set_mtrr in intel_subr.c and mtrr.c in linux kernel
- *
- * Copyright 2000 Silicon Integrated System Corporation
- * Copyright 2013 Google Inc.
+ * This file is part of the coreboot project.
  *
  *	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
@@ -16,6 +11,8 @@
  *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *	GNU General Public License for more details.
  *
+ * mtrr.c: setting MTRR to decent values for cache initialization on P6
+ * Derived from intel_set_mtrr in intel_subr.c and mtrr.c in linux kernel
  *
  * Reference: Intel Architecture Software Developer's Manual, Volume 3: System
  * Programming