m68k: Replace GPL 2.0+ README.legal boilerplate with SPDX

Upstream Linux never had a "README.legal" file, but it was present
in early source releases of Linux/m68k.  It contained a simple copyright
notice and a link to a version of the "COPYING" file that predated the
addition of the "only valid GPL version is v2" clause.

Get rid of the references to non-existent files by replacing the
boilerplate with SPDX license identifiers.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/23430c233728ab02ec0af8e714994398d383137a.1695031668.git.geert@linux-m68k.org

arch/m68k/68000/entry.S

-/*
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ *
  *  entry.S -- non-mmu 68000 interrupt and exception entry points
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
- *
  * Linux/m68k support by Hamish Macdonald
  */
 

arch/m68k/bvme6000/config.c

+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  arch/m68k/bvme6000/config.c
  *
@@ -8,10 +9,6 @@
  *  linux/amiga/config.c
  *
  *  Copyright (C) 1993 Hamish Macdonald
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
  */
 
 #include <linux/types.h>

arch/m68k/coldfire/entry.S

-/*
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ *
  *  entry.S  -- interrupt and exception processing for ColdFire
  *
  *  Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
@@ -13,10 +14,6 @@
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
- *
  * Linux/m68k support by Hamish Macdonald
  *
  * 68060 fixes by Jesper Skov

arch/m68k/ifpsp060/Makefile

-# Makefile for 680x0 Linux 68060 integer/floating point support package
+# SPDX-License-Identifier: GPL-2.0-or-later
 #
-# This file is subject to the terms and conditions of the GNU General Public
-# License.  See the file "README.legal" in the main directory of this archive
-# for more details.
+# Makefile for 680x0 Linux 68060 integer/floating point support package
 
 obj-y := fskeleton.o iskeleton.o os.o

arch/m68k/kernel/entry.S

-/* -*- mode: asm -*-
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * -*- mode: asm -*-
  *
  *  linux/arch/m68k/kernel/entry.S
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds
  *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
- *
  * Linux/m68k support by Hamish Macdonald
  *
  * 68060 fixes by Jesper Skov

arch/m68k/kernel/head.S

-/* -*- mode: asm -*-
+/* SPDX-License-Identifier: GPL-2.0-or-later
+** -*- mode: asm -*-
 **
 ** head.S -- This file contains the initial boot code for the
 **	     Linux/68k kernel.
@@ -25,11 +26,6 @@
 **            for linux-2.1.115
 ** 1999/02/11  Richard Zidlicky: added Q40 support (initial version 99/01/01)
 ** 2004/05/13 Kars de Jong: Finalised HP300 support
-**
-** This file is subject to the terms and conditions of the GNU General Public
-** License. See the file README.legal in the main directory of this archive
-** for more details.
-**
 */
 
 /*

arch/m68k/mvme147/config.c

+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  arch/m68k/mvme147/config.c
  *
@@ -7,10 +8,6 @@
  * Based on:
  *
  *  Copyright (C) 1993 Hamish Macdonald
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
  */
 
 #include <linux/types.h>

arch/m68k/mvme16x/config.c

+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  arch/m68k/mvme16x/config.c
  *
@@ -8,10 +9,6 @@
  *  linux/amiga/config.c
  *
  *  Copyright (C) 1993 Hamish Macdonald
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
  */
 
 #include <linux/types.h>

arch/m68k/q40/config.c

+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  arch/m68k/q40/config.c
  *
@@ -6,10 +7,6 @@
  * originally based on:
  *
  *  linux/bvme/config.c
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file README.legal in the main directory of this archive
- * for more details.
  */
 
 #include <linux/errno.h>