This patch adds support to program TrustZone protection on ARM platforms that
implement a DMC-500. arm_dmc_500.c has been added which implements the
arm_dmc_tzc_setup() function. This function relies on constants related to TZC
programming that are exported by each platform to program TrustZone protection
using the DMC-500 TrustZone controller driver. This function should be called
from plat_arm_security_setup() which is implemented by each platform.

Change-Id: I5400bdee9e4b29155fd11296a40693d512312f29