SPDX: Convert all of our single license tags to Linux Kernel style

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/tcl/sl50/Makefile b/board/tcl/sl50/Makefile
index d4a548c..c2977d7 100644
--- a/board/tcl/sl50/Makefile
+++ b/board/tcl/sl50/Makefile
@@ -1,10 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0+
 #
 # Makefile
 #
 # Copyright (C) 2015 Toby Churchill Ltd - http://www.toby-churchill.com/
-#
-# SPDX-License-Identifier:	GPL-2.0+
-#
 
 ifeq ($(CONFIG_SKIP_LOWLEVEL_INIT),)
 obj-y	:= mux.o
diff --git a/board/tcl/sl50/board.c b/board/tcl/sl50/board.c
index 933a407..6bb6482 100644
--- a/board/tcl/sl50/board.c
+++ b/board/tcl/sl50/board.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * board.c
  *
  * Board functions for TCL SL50 board
  *
  * Copyright (C) 2011, Texas Instruments, Incorporated - http://www.ti.com/
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>
diff --git a/board/tcl/sl50/board.h b/board/tcl/sl50/board.h
index ae2ef6b..b8b9ed7 100644
--- a/board/tcl/sl50/board.h
+++ b/board/tcl/sl50/board.h
@@ -1,11 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * board.h
  *
  * TCL SL50 boards information header
  *
  * Copyright (C) 2011, Texas Instruments, Incorporated - http://www.ti.com/
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef _BOARD_H_
diff --git a/board/tcl/sl50/mux.c b/board/tcl/sl50/mux.c
index e0d76ef..b0a1dad 100644
--- a/board/tcl/sl50/mux.c
+++ b/board/tcl/sl50/mux.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * mux.c
  *
  * Copyright (C) 2011, Texas Instruments, Incorporated - http://www.ti.com/
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>