feat(rdn2): add dts for secure partition

This patch adds dts for Standalone MM used as S-EL0 SP on RD-N2
platform.

Signed-off-by: Sayanta Pattanayak <sayanta.pattanayak@arm.com>
Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: I9f1a6825d43f8be1c4bdeb98d9d7267b595e2b76
3 files changed