FVP: map non-secure DRAM1 in the MMU ...

This patch maps the non-secure region of DRAM1 in the MMU. The
non-secure region comprises the whole DRAM1 (0x80000000 -
0xffffffff) excluding the top 16 MB (0xff000000 - 0xffffffff).
The TrustZone controller configures this 16 MB region as secure
memory, so it can not be accessed in non-secure mode.

The number of MMU tables in BL2 has been increased to 3 because
the new size of the non-secure region in DRAM requires an extra L2
table.

Change-Id: I5ad080c6e181f6b6060e15cebb1d18b7fa128cf5

Simplify interface to TZC-400 driver ...

The TZC-400 driver previously allowed the possibility of multiple
controller instances to be present in the same executable. This
was unnecessary since there will only ever be one instance.

This change simplifies the tzc_init() function to only take the
base address argument needed by implementation, conforming to the
driver initialization model of other drivers. It also hides some
of the implementation details that were previously exposed by the
API.

The FVP port has been updated accordingly.

THIS CHANGE REQUIRES ALL PLATFORM PORTS THAT USE THE TZC-400
DRIVER TO BE UPDATED

Fixes ARM-software/tf-issues#181

Change-Id: I7b721edf947064989958d8f457d6462d92e742c8

Refactor fvp_config into common platform header ...

Changed the fvp_config array in fvp_common.c into a struct and
moved into a new optional common platform header,
include/plat/common/plat_config.h. Removed the config definitions
in fvp_def.h and updated all references to the platform config.

This makes the interface to the platform config cleaner and uses
a little less RAM.

Fixes ARM-software/tf-issues#180

Change-Id: I58dd7b3c150f24f7ee230a26fd57c827853ba803

Rename FVP specific files and functions ...

FVP specific files and functions containing the word "plat" have been
renamed to use the word "fvp" to distinguish them from the common
platform functionality and porting functions.

Change-Id: I39f9673dab3ee9c74bd18b3e62b7c21027232f7d