plat/arm: Add platform support for Morello

This patch adds support for Morello platform.
It is an initial port which includes only BL31 support
as the System Control Processor (SCP) is expected to take
the role of primary bootloader.

Change-Id: I1ecbe5a14a2d487b2ecea3c1ca227f08473ed2dd
Co-authored-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
Signed-off-by: Anurag Koul <anurag.koul@arm.com>
diff --git a/docs/plat/index.rst b/docs/plat/index.rst
index bd23410..fb60e56 100644
--- a/docs/plat/index.rst
+++ b/docs/plat/index.rst
@@ -54,6 +54,7 @@
    - Arm Neoverse Reference Design E1 Edge (RD-E1-Edge) FVP
    - Arm SGI-575 and SGM-775
    - MediaTek MT6795 and MT8173 SoCs
+   - Arm Morello Platform
 
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