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>

includes: move openssl headers to include/u-boot

commit 18b06652cd "tools: include u-boot version of sha256.h"
unconditionally forced the sha256.h from u-boot to be used
for tools instead of the host version. This is fragile though
as it will also include the host version. Therefore move it
to include/u-boot to join u-boot/md5.h etc which were renamed
for the same reason.

cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

Add dumpimage, a tool to extract data from U-Boot images

Given a multi-file image created through the mkimage's -d option:

$ mkimage -A x86 -O linux -T multi -n x86 -d vmlinuz:initrd.img:System.map \
multi.img

Image Name: x86
Created: Thu Jul 25 10:29:13 2013
Image Type: Intel x86 Linux Multi-File Image (gzip compressed)
Data Size: 13722956 Bytes = 13401.32 kB = 13.09 MB
Load Address: 00000000
Entry Point: 00000000
Contents:
Image 0: 4040128 Bytes = 3945.44 kB = 3.85 MB
Image 1: 7991719 Bytes = 7804.41 kB = 7.62 MB
Image 2: 1691092 Bytes = 1651.46 kB = 1.61 MB

It is possible to perform the innverse operation -- extracting any file from
the image -- by using the dumpimage's -i option:

$ dumpimage -i multi.img -p 2 System.map

Although it's feasible to retrieve "data files" from image through scripting,
the requirement to embed tools such 'dd', 'awk' and 'sed' for this sole purpose
is cumbersome and unreliable -- once you must keep track of file sizes inside
the image. Furthermore, extracting data files using "dumpimage" tool is faster
than through scripting.

Signed-off-by: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
Signed-off-by: Simon Glass <sjg@chromium.org>