Add support for specifying pre-built BL binaries in Makefile

This patch adds support for supplying pre-built BL binaries for BL2,
BL3-1 and BL3-2 during trusted firmware build. Specifying BLx = <path_to_BLx>
in the build command line, where 'x' is any one of BL2, BL3-1 or BL3-2, will
skip building that BL stage from source and include the specified binary in
final fip image.

This patch also makes BL3-3 binary for FIP optional depending on the
value of 'NEED_BL33' flag which is defined by the platform.

Fixes ARM-software/tf-issues#244
Fixes ARM-software/tf-issues#245

Change-Id: I3ebe1d4901f8b857e8bb51372290978a3323bfe7
Merge pull request #210 from soby-mathew/sm/makefile_bl_stages

Add support for specifying pre-built BL binaries in Makefile
Initialize SCTLR_EL1 based on MODE_RW bit

Initializes SCTLR_EL1 based on MODE_RW bit in SPSR for the entry
point. The RES1 bits for SCTLR_EL1 differs for Aarch64 and Aarch32
mode.
Add opteed based on tspd

Adds a dispatcher for OP-TEE based on the test secure payload
dispatcher.

Fixes arm-software/tf-issues#239
Merge pull request #211 from jenswi-linaro/optee_140916

Dispatcher for OPTEE from Linaro SWG
Fix LENGTH attribute value in linker scripts

This patch fixes the incorrect value of the LENGTH attribute in
the linker scripts. This attribute must define the memory size, not
the limit address.

Fixes ARM-software/tf-issues#252

Change-Id: I328c38b9ec502debe12046a8912d7dfc54610c46
Merge pull request #212 from jcastillo-arm/jc/tf-issues/252

Fix LENGTH attribute value in linker scripts
Remove BSS section access by 'plat_print_gic' during crash reporting

This patch avoids the problem of crash reporting mechanism accessing
global data in BSS by 'plat_print_gic_regs' for FVP platforms. Earlier
it depended on the global 'plat_config' object for the GIC Base address
in FVP platforms which would have caused exception if it were accessed
before the BSS was initialized. It is now fixed by dynamically
querying the V2M_SYS_ID to find the FVP model type and accordingly
selecting the appropriate GIC Base address.

This patch also fixes the 'plat_print_gic_regs' to use the correct GIC
Distributor base address for printing GICD_IS_PENDR register values
for both Juno and FVP platforms.

Fixes ARM-Software/tf-issues#236

Change-Id: I545c7b908b3111419bf27db0575ce86acf86784b
Merge pull request #213 from soby-mathew/sm/crash_reporting_fix

Remove BSS section access by 'plat_print_gic' during crash reporting
Create BL stage specific translation tables

This patch uses the IMAGE_BL<x> constants to create translation tables specific
to a boot loader stage. This allows each stage to create mappings only for areas
in the memory map that it needs.

Fixes ARM-software/tf-issues#209

Change-Id: Ie4861407ddf9317f0fb890fc7575eaa88d0de51c
Merge pull request #214 from soby-mathew/sm/bl_specific_mmap

Create BL stage specific translation tables