Build the imx code singing tool from source instead of relying on the
distro to provide the tool.
Use the debian/unstable branch because the default branch is outdated.
The binary is supposed to be build with docker, work around that by selecting
the correct Makefile directly.
Also append the description and add a link to documentation.

Signed-off-by: Leonard Anderweit <l.anderweit@phytec.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

Binman needs the ability to run fdtgrep to prepare devicetree subsets
for use by SPL and TPL. Add a new bintool in preparation for this.

Signed-off-by: Simon Glass <sjg@chromium.org>

The docs have somehow got out of sync. Regenerate the file to fix the
problem.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add the Xilinx Bootgen as bintool. Xilinx Bootgen is used to create
bootable SPL (FSBL in Xilinx terms) images for Zynq/ZynqMP devices. The
btool creates a signed version of the SPL. Additionally to signing the
key source for the decryption engine can be passend to the boot image.

Signed-off-by: Lukas Funke <lukas.funke@weidmueller.com>

Add documentation for the 'bootgen' bintool

Signed-off-by: Lukas Funke <lukas.funke@weidmueller.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Add documentation for btool which calls 'fdt_add_pubkey'

Signed-off-by: Lukas Funke <lukas.funke@weidmueller.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Rerun 'binman bintool-docs' to regenerate bintools.rst

Signed-off-by: Simon Glass <sjg@chromium.org>

This was not regenerated with recent changes. Update it.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add this documention to explain how bintools are used and which ones are
available.

Signed-off-by: Simon Glass <sjg@chromium.org>