Reserve some DDR DRAM for secure use on FVP platforms ...

TZC-400 is configured to set the last 16MB of DRAM1 as secure memory and
the rest of DRAM as non-secure. Non-secure software must not attempt to
access the 16MB secure area.

Device tree files (sources and binaries) have been updated to match this
configuration, removing that memory from the Linux physical memory map.

To use UEFI and Linux with this patch, the latest version of UEFI and
the updated device tree files are required. Check the user guide in the
documentation for more details.

Replaced magic numbers with #define for memory region definition in the
platform security initialization function.

Fixes ARM-software/tf-issues#149

Change-Id: Ia5d070244aae6c5288ea0e6c8e89d92859522bfe

Enable secure memory support for FVPs ...

- Use the TrustZone controller on Base FVP to program DRAM access
  permissions. By default no access to DRAM is allowed if
  'secure memory' is enabled on the Base FVP.
- The Foundation FVP does not have a TrustZone controller but instead
  has fixed access permissions.
- Update FDTs for Linux to use timers at the correct security level.
- Starting the FVPs with 'secure memory' disabled is also supported.

Limitations:
Virtio currently uses a reserved NSAID. This will be corrected in
future FVP releases.

Change-Id: I0b6c003a7b5982267815f62bcf6eb82aa4c50a31

Increase default amount of RAM for Base FVPs in FDTs ...

- Large RAM-disks may have trouble starting with 2GB of memory.
- Increase from 2GB to 4GB in FDT.

Change-Id: I12c1b8e5db41114b88c69c48621cb21247a6a6a7

Add GICv3 ITS to FDTs ...

- The interrupt addresses need to be updated to work.

Change-Id: Icdd00177095ae9e4eb7b13718762f92e29b1465c

ARMv8 Trusted Firmware release v0.2