feat(board/rdn2): add support for variant 1 of rd-n2 platform

Add board support for RD-N2 Cfg1 variant of RD-N2 platform. It is a
variant of RD-N2 platform with a reduced interconnect mesh size (3x3)
and core count (8-cores). Its platform variant id is 1.

Change-Id: I34ad35c5a5c1e9b69a658fb92ed00e5bc5fe72f3
Signed-off-by: Aditya Angadi <aditya.angadi@arm.com>
5 files changed