This patch modifies the Trusted Board Boot implementation to use
the new authentication framework, making use of the authentication
module, the cryto module and the image parser module to
authenticate the images in the Chain of Trust.

A new function 'load_auth_image()' has been implemented. When TBB
is enabled, this function will call the authentication module to
authenticate parent images following the CoT up to the root of
trust to finally load and authenticate the requested image.

The platform is responsible for picking up the right makefiles to
build the corresponding cryptographic and image parser libraries.
ARM platforms use the mbedTLS based libraries.

The platform may also specify what key algorithm should be used
to sign the certificates. This is done by declaring the 'KEY_ALG'
variable in the platform makefile. FVP and Juno use ECDSA keys.

On ARM platforms, BL2 and BL1-RW regions have been increased 4KB
each to accommodate the ECDSA code.

REMOVED BUILD OPTIONS:

  * 'AUTH_MOD'

Change-Id: I47d436589fc213a39edf5f5297bbd955f15ae867

Move the Juno port from plat/juno to plat/arm/board/juno. Also rename
some of the files so they are consistently prefixed with juno_.
Update the platform makefiles accordingly.

Change-Id: I0af6cb52a5fee7ef209107a1188b76a3c33a2a9f