fix(granules): granule_addr() did not detect a misaligned address

granule_addr() API on the granule module of the realm library should
cause an assertion failure when the struct granule address pointer
received as parameter is not properly aligned.

This patch also adds the proper unittest to verify the condition.

Signed-off-by: Javier Almansa Sobrino <javier.almansasobrino@arm.com>
Change-Id: I49df885af5dc346c33c04bc88fcdc1db36f75fcd