n1sdp: add memory map include files for n1sdp SCP

This patch adds the following header files:

n1sdp_scp_mmap.h -> N1SDP SCP's peripheral memory mapping information.
n1sdp_scp_software_mmap.h -> Definitions of software mapping of
                             hardware memories.
n1sdp_scp_system_mmap.h -> Definitions of external & internal
                           memories connected to SCP.

Change-Id: I31a12498ec04e7cf602144a6afc159806714fa69
Signed-off-by: Manoj Kumar <manoj.kumar3@arm.com>