product/rdn2: update CPU info in SDS

Update CPU info in SDS. The CPU info contains the logical ID of
the primary boot CPU on the platform and this is picked up from the
platform system module's context information.

Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: Ib9085e04c63509f3af36aff4dbdf8ae274c48648