romlib: Add platform specific jump table list ...

This patch allows platforms to define their
own jump table list for library at ROM. The
file has the list of functions to be used
from library at ROM. It can also include
other list files.

Change-Id: I721c35d7dad3dcadbb3a7f3277bfd5d3e1f6e00a
Signed-off-by: Sathees Balya <sathees.balya@arm.com>

Add support for romlib in the build system ...

Romlib is a new image that is stored in ROM and contains the code of
several libraries that can be shared between different images. All
the functions within in the library are accessed using a jump table
which allows to update the romlib image whithout changing the binary
compatibility. This jump table can be also stored in RAM and it can
allow to patch a romlib with potential bugs fixes..

Change-Id: If980ccdaca24b7aaca900e32acc68baf6f94ab35
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>