FVP: Ensure system reset wake-up results in cold boot

platform_get_entrypoint() did not consider that a wakeup due to
System Reset Pin (by reading the power controller's PSYSR) requires
a cold boot. As a result, the code would execute the warm boot path
and eventually panic because entrypoint mailboxes are empty.

This patch ensures that the following wake-up reasons result in cold
boot:
  - Cold Power-on
  - System Reset Pin (includes reset by software)

Fixes ARM-software/tf-issues#217

Change-Id: I65ae0a0f7a46548b575900a5aac107d352b0e2cd
Define ARM_GIC_ARCH default value for all platforms

The ARM_GIC_ARCH build option was supposed to default to 2 on all
platforms. However, the default value was set in the FVP makefile
so for all other platforms it wasn't even defined.

This patch moves the default value to the main Makefile. The platform
port can then override it if needed.

Change-Id: I8e2da1cce7ffa3ed18814bbdcbcf2578101f18a6
Implement a leaner printf for Trusted Firmware

This patch implements a "tf_printf" which supports only the commonly
used format specifiers in Trusted Firmware, which uses a lot less
stack space than the stdlib printf function.

Fixes ARM-software/tf-issues#116

Change-Id: I7dfa1944f4c1e634b3e2d571f49afe02d109a351
Merge pull request #174 from soby-mathew:sm/lean_printf_v2

Implement a leaner printf for Trusted Firmware
Merge pull request #168 from sandrine-bailleux/sb/set-default-gic-arch

Define ARM_GIC_ARCH default value for all platforms
Merge pull request #167 from jcastillo-arm/jc/tf-issues/217

FVP: Ensure system reset wake-up results in cold boot
Add support for printing version at runtime

Print out Trusted Firmware version at runtime at each BL stage.
Message consists of TF version as defined statically in the Makefile
(e.g. v0.4), build mode (debug|release) and a customizable build
string:

  1. By defining BUILD_STRING in command line when building TF
  2. Default string is git commit ID
  3. Empty if git meta-data is not available

Fixes ARM-software/tf-issues#203

Change-Id: I5c5ba438f66ab68810427d76b49c5b9177a957d6
Merge pull request #176 from danh-arm/jc/tf-issues/203-v3

Add support for printing version at runtime v3