Some of the Reference Design platforms like RD-N1-Edge can operate in
multi-chip configuration wherein two or more SoCs are connected through
a high speed coherent CCIX link. For the RD platforms, the remote chip
address space is at the offset of 4TB per chip. In order for the primary
chip to access the device memory region on the remote chip, the required
memory region entries need to be added as mmap entry. This patch adds
macros related to the remote chip device memory region.

Change-Id: I833810b96f1a0e7c3c289ac32597b6ba03344c80
Signed-off-by: Vijayenthiran Subramaniam <vijayenthiran.subramaniam@arm.com>