N1SDP supports multichip configuration wherein n1sdp boards are
connected over high speed coherent CCIX link  for now only dual-chip is
supported.

A single instance of TF-A runs on master chip which should be aware of
slave chip's CPU and memory topology.

This patch updates platform macros to include remote chip's information
and also ensures that a single version of firmware works for both single
and dual-chip setup.

Change-Id: I75799fd46dc10527aa99585226099d836c21da70
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>