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/include/environment/ti/boot.h b/include/environment/ti/boot.h
index 24b7783..31042fa 100644
--- a/include/environment/ti/boot.h
+++ b/include/environment/ti/boot.h
@@ -1,10 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Boot related environment variable definitions on TI boards.
  *
  * (C) Copyright 2017 Linaro Ltd.
  * Sam Protsenko <semen.protsenko@linaro.org>
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __TI_BOOT_H
diff --git a/include/environment/ti/dfu.h b/include/environment/ti/dfu.h
index c89005f..9f7ea03 100644
--- a/include/environment/ti/dfu.h
+++ b/include/environment/ti/dfu.h
@@ -1,9 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com
  *
  * Environment variable definitions for DFU on TI boards.
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __TI_DFU_H
diff --git a/include/environment/ti/mmc.h b/include/environment/ti/mmc.h
index 4305ebd..785fc15 100644
--- a/include/environment/ti/mmc.h
+++ b/include/environment/ti/mmc.h
@@ -1,9 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com
  *
  * Environment variable definitions for MMC/SD on TI boards.
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __TI_MMC_H
diff --git a/include/environment/ti/spi.h b/include/environment/ti/spi.h
index 18c857c..1681dc8 100644
--- a/include/environment/ti/spi.h
+++ b/include/environment/ti/spi.h
@@ -1,9 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright (C) 2017 Texas Instruments Incorporated - http://www.ti.com
  *
  * Environment variable definitions for SPI on TI boards.
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __TI_SPI_H