docs: marvell: Add information about CZ.NIC Armada 3720 Secure Firmware

CZ.NIC as part of Turris project released free and open source WTMI
application firmware 'wtmi_app.bin' for all Armada 3720 devices. This
firmware includes additional features like access to Hardware Random
Number Generator of Armada 3720 SoC which original Marvell's 'fuse.bin'
image does not have.

CZ.NIC's Armada 3720 Secure Firmware is available at website:

    https://gitlab.nic.cz/turris/mox-boot-builder/

This change updates documentation to include steps how to build Marvell
firmware image for Espressobin with this firmware to enable Hardware
Random Number Generator on Espressobin.

In this change is fixed also URL to TF-A and U-Boot git repositories in
Espressobin build example. And as Marvell github repositories switched
default branch to master, explicit branch via -b parameter is redundant
and therefore from examples removed.

Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I59ee29cb6ed149264c5e4202f2af8f9ab3859418
1 file changed