Platform information structure holds information about platform's DDR
size(local/remote) which will be used to zero out the memory before
enabling the ECC capability as well as information about multichip
setup. Multichip and remote DDR information can only be probed in SCP,
SDS region will be used by TF-A to get this information at boot up.

This patch introduces a new SDS to store platform information, which is
populated dynamically by SCP Firmware.previously used mem_info SDS is
also made part of this structure itself.

The platform information is also passed to BL33 by copying it to Non-
Secure SRAM.

Change-Id: I4781dc6a7232c3c0a3219b164d943ce9e3e469ee
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>