gpt: added unit tests for GPT at L0

This patch adds unit tests for the Granule Protection Table at
level 0. It also includes some utilities that help handling the
tables.

The patch includes L0 table initialization, table alignment (and
misalignment) and table (right and wrong) size tests.

Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Co-developed-by: Kathleen Capella <kathleen.capella@arm.com>
Change-Id: Id5b449b193a4d4021143745e1e9fa54dbaaf506e
12 files changed