Use the firmware configuration framework to retrieve information about
Secure Partitions to facilitate loading them into memory.

To load a SP image we need UUID look-up into FIP and the load address
where it needs to be loaded in memory.

This patch introduces a SP populator function which gets UUID and load
address from firmware config device tree and updates its C data
structure.

Change-Id: I17faec41803df9a76712dcc8b67cadb1c9daf8cd
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>