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/net/Makefile b/net/Makefile
index ce6e5ad..d1e8e01 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -1,9 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
 #
 # (C) Copyright 2000-2006
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
-#
-# SPDX-License-Identifier:	GPL-2.0+
-#
 
 #ccflags-y += -DDEBUG
 
diff --git a/net/checksum.c b/net/checksum.c
index a8c9ff5..16ef416 100644
--- a/net/checksum.c
+++ b/net/checksum.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
 /*
  * This file was originally taken from the FreeBSD project.
  *
  * Copyright (c) 2001 Charles Mott <cm@linktel.net>
  * Copyright (c) 2008 coresystems GmbH
  * All rights reserved.
- *
- * SPDX-License-Identifier:	BSD-2-Clause
  */
 
 #include <common.h>
diff --git a/net/dns.h b/net/dns.h
index c55a5c1..79ac76f 100644
--- a/net/dns.h
+++ b/net/dns.h
@@ -1,8 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * (C) Masami Komiya <mkomiya@sonare.it> 2005
  *  Copyright 2009, Robin Getz <rgetz@blackfin.uclinux.org>
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __DNS_H__
diff --git a/net/eth-uclass.c b/net/eth-uclass.c
index 240b596..d20a1cf 100644
--- a/net/eth-uclass.c
+++ b/net/eth-uclass.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2001-2015
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  * Joe Hershberger, National Instruments
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>
diff --git a/net/eth_common.c b/net/eth_common.c
index 0af91a9..63f9379 100644
--- a/net/eth_common.c
+++ b/net/eth_common.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2001-2015
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  * Joe Hershberger, National Instruments
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>
diff --git a/net/eth_internal.h b/net/eth_internal.h
index 4b0e716..faff0ef 100644
--- a/net/eth_internal.h
+++ b/net/eth_internal.h
@@ -1,9 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * (C) Copyright 2001-2015
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  * Joe Hershberger, National Instruments
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __ETH_INTERNAL_H
diff --git a/net/eth_legacy.c b/net/eth_legacy.c
index be0cf64..2a9caa3 100644
--- a/net/eth_legacy.c
+++ b/net/eth_legacy.c
@@ -1,9 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2001-2015
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  * Joe Hershberger, National Instruments
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>
diff --git a/net/nfs.h b/net/nfs.h
index 1aa06e8..6359cd2 100644
--- a/net/nfs.h
+++ b/net/nfs.h
@@ -1,7 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * (C) Masami Komiya <mkomiya@sonare.it> 2004
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __NFS_H__
diff --git a/net/rarp.c b/net/rarp.c
index 1fa11b6..c1d9fca 100644
--- a/net/rarp.c
+++ b/net/rarp.c
@@ -1,8 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2000-2002
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #include <common.h>
diff --git a/net/rarp.h b/net/rarp.h
index 1ca8833..de4504e 100644
--- a/net/rarp.h
+++ b/net/rarp.h
@@ -1,8 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * (C) Copyright 2000
  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #if defined(CONFIG_CMD_RARP)
diff --git a/net/sntp.h b/net/sntp.h
index c38bcee..d3cbfbc 100644
--- a/net/sntp.h
+++ b/net/sntp.h
@@ -1,7 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * (C) Masami Komiya <mkomiya@sonare.it> 2005
- *
- * SPDX-License-Identifier:	GPL-2.0+
  */
 
 #ifndef __SNTP_H__