cpu: add support for Demeter CPU

This patch adds the basic CPU library code to support the Demeter
CPU.  This CPU is based on the Makalu-ELP core so that CPU lib code
was adapted to create this patch.

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: Ib5740b748008a72788c557f0654d8d5e9ec0bb7f
3 files changed