Extend SPSR definitions for full use of ELx modes

Extended SPSR definitions with all the fields to allow full use
of EL2/EL1 execution modes for entry points
Replaced make_spsr() with SPSR_64 macro and added SPSR_32 macro
for generating AARCH32 mode SPSR

Change-Id: I9425dda0923e8d5f03d03ddb8fa0e28392c4c61e
Rework handover interface between BL stages

This patch reworks the handover interface from: BL1 to BL2 and
BL2 to BL3-1. It removes the raise_el(), change_el(), drop_el()
and run_image() functions as they catered for code paths that were
never exercised.
BL1 calls bl1_run_bl2() to jump into BL2 instead of doing the same
by calling run_image(). Similarly, BL2 issues the SMC to transfer
execution to BL3-1 through BL1 directly. Only x0 and x1 are used
to pass arguments to BL31. These arguments and parameters for
running BL3-1 are passed through a reference to a
'el_change_info_t' structure. They were being passed value in
general purpose registers earlier.

Change-Id: Id4fd019a19a9595de063766d4a66295a2c9307e1
Populate BL31 input parameters as per new spec

This patch is based on spec published at
https://github.com/ARM-software/tf-issues/issues/133

It rearranges the bl31_args struct into
bl31_params and bl31_plat_params which provide the
information needed for Trusted firmware and platform
specific data via x0 and x1

On the FVP platform BL3-1 params and BL3-1 plat params
and its constituents are stored at the start of TZDRAM.

The information about memory availability and size for
BL3-1, BL3-2 and BL3-3 is moved into platform specific data.

Change-Id: I8b32057a3d0dd3968ea26c2541a0714177820da9
Rework memory information passing to BL3-x images

The issues addressed in this patch are:

1. Remove meminfo_t from the common interfaces in BL3-x,
expecting that platform code will find a suitable mechanism
to determine the memory extents in these images and provide
it to the BL3-x images.

2. Remove meminfo_t and bl31_plat_params_t from all FVP BL3-x
code as the images use link-time information to determine
memory extents.

meminfo_t is still used by common interface in BL1/BL2 for
loading images

Change-Id: I4e825ebf6f515b59d84dc2bdddf6edbf15e2d60f
Add support for BL3-1 as a reset vector

This change adds optional reset vector support to BL3-1
which means BL3-1 entry point can detect cold/warm boot,
initialise primary cpu, set up cci and mail box.

When using BL3-1 as a reset vector it is assumed that
the BL3-1 platform code can determine the location of
the BL3-2 images, or load them as there are no parameters
that can be passed to BL3-1 at reset.

It also fixes the incorrect initialisation of mailbox
registers on the FVP platform

This feature can be enabled by building the code with
make variable RESET_TO_BL31 set as 1

Fixes ARM-software/TF-issues#133
Fixes ARM-software/TF-issues#20

Change-Id: I4e23939b1c518614b899f549f1e8d412538ee570
TSP: Let the platform decide which secure memory to use

The TSP's linker script used to assume that the TSP would
execute from secure DRAM. Although it is currently the case
on FVPs, platforms are free to use any secure memory they wish.

This patch introduces the flexibility to load the TSP into any
secure memory. The platform code gets to specify the extents of
this memory in the platform header file, as well as the BL3-2 image
limit address. The latter definition allows to check in a generic way
that the BL3-2 image fits in its bounds.

Change-Id: I9450f2d8b32d74bd00b6ce57a0a1542716ab449c
fvp: Move TSP from Secure DRAM to Secure SRAM

The TSP used to execute from secure DRAM on the FVPs because there was
not enough space in Trusted SRAM to fit it in. Thanks to recent RAM
usage enhancements being implemented, we have made enough savings for
the TSP to execute in SRAM.

However, there is no contiguous free chunk of SRAM big enough to hold
the TSP. Therefore, the different bootloader images need to be moved
around to reduce memory fragmentation. This patch keeps the overall
memory layout (i.e. keeping BL1 R/W at the bottom, BL2 at the top and
BL3-1 in between) but moves the base addresses of all the bootloader
images in such a way that:
 - memory fragmentation is reduced enough to fit BL3-2 in;
 - new base addresses are suitable for release builds as well as debug
   ones;
 - each image has a few extra kilobytes for future growth.
   BL3-1 and BL3-2 are the images which received the biggest slice
   of the cake since they will most probably grow the most.

A few useful numbers for reference (valid at the time of this patch):
        |-----------------------|-------------------------------
        |  image size (debug)   |  extra space for the future
--------|-----------------------|-------------------------------
BL1 R/W |         20 KB         |            4 KB
BL2     |         44 KB         |            4 KB
BL3-1   |        108 KB         |           12 KB
BL3-2   |         56 KB         |            8 KB
--------|-----------------------|-------------------------------
Total   |        228 KB         |           28 KB       = 256 KB
--------|-----------------------|-------------------------------

Although on FVPs the TSP now executes from Trusted SRAM by default,
this patch keeps the option to execute it from Trusted DRAM. This is
controlled by the build configuration 'TSP_RAM_LOCATION'.

Fixes ARM-Software/tf-issues#81

Change-Id: Ifb9ef2befa9a2d5ac0813f7f79834df7af992b94
Doc: Add the "Building the Test Secure Payload" section

Add a section in the user guide explaining how to compile the TSP
image and include it into the FIP. This includes instructions to make
the TSP run from Trusted DRAM (rather than Trusted SRAM) on FVP.

Change-Id: I04780757a149eeb5482a12a61e821be947b882c0