Revert accidental removal of BL2 from help message

Commit 375f538a7 in Github accidentally removed the BL2 targets from the
Makefile help message. This patch reverts that change.

Change-Id: I825a9abe5b4ba0f15d02879dda1056912e2ad60c
Reduce GICv3 debug output

Change-Id: Ia8502f8d0566025d8bad150029f49cb63815261d
Update contributing.md to new CLA location

This commit updates contributing.md to point to the ARM website
for downloading copies of the Contribution License Agreement (CLA).
It is no longer necessary to email ARM for these.

Change-Id: Iaf58680631a626f26827577709ac5471e3b84566
Implement late binding for runtime hooks

At present SPD power management hooks and BL3-2 entry are implemented
using weak references. This would have the handlers bound and registered
with the core framework at build time, but leaves them dangling if a
service fails to initialize at runtime.

This patch replaces implementation by requiring runtime handlers to
register power management and deferred initialization hooks with the
core framework at runtime. The runtime services are to register the
hooks only as the last step, after having all states successfully
initialized.

Change-Id: Ibe788a2a381ef39aec1d4af5ba02376e67269782
Tolerate runtime service initialization failure

At present, the firmware panics if a runtime service fails to
initialize. An earlier patch had implemented late binding for all
runtime service handlers.

With that in place, this patch allows the firmware to proceed even when
a service fails to initialize.

Change-Id: I6cf4de2cecea9719f4cd48272a77cf459b080d4e
fvp: Initialise UART earlier

The UART used to be initialised in bl1_platform_setup(). This is too
late because there are some calls to the assert() macro, which needs
to print some messages on the console, before that.

This patch moves the UART initialisation code to
bl1_early_platform_setup().

Fixes ARM-software/tf-issues#49

Change-Id: I98c83a803866372806d2a9c2e1ed80f2ef5b3bcc
Remove duplicate xlat_table descriptions

The BL31 and BL2 linker scripts ended up having duplicate descriptions
for xlat_tables section. This patch removes those duplicate
descriptions.

Change-Id: Ibbdda0902c57fca5ea4e91e0baefa6df8f0a9bb1