This patch introduces a better separation between the trusted-boot
related properties, and the dynamic configuration DTBs loading
information.

The dynamic configuration DTBs properties are moved to a new node:
`dtb-registry`. All the sub-nodes present will be provided to the
dynamic config framework to be loaded. The node currently only contains
the already defined configuration DTBs, but can be extended for future
features if necessary.
The dynamic config framework is modified to use the abstraction provided
by the fconf framework, instead of directly accessing the DTBs.

The trusted-boot properties are kept under the "arm,tb_fw" compatible
string, but in a separate `tb_fw-config` node.
The `tb_fw-config` property of the `dtb-registry` node simply points
to the load address of `fw_config`, as the `tb_fw-config` is currently
part of the same DTB.

Change-Id: Iceb6c4c2cb92b692b6e28dbdc9fb060f1c46de82
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>

This patch adds support for Versatile express FVP (Fast models).
Versatile express is a family of platforms that are based on ARM v7.
Currently this port has only been tested on Cortex A7, although it
should work with other ARM V7 cores that support LPAE, generic timers,
VFP and hardware divide. Future patches will support other
cores like Cortex A5 that dont support features like LPAE
and hardware divide. This platform is tested on and only expected to
work on single core models.

Change-Id: I10893af65b8bb64da7b3bd851cab8231718e61dd
Signed-off-by: Usama Arif <usama.arif@arm.com>