feat(plat/st): add a new DDR firewall management

Based on FCONF framework, define DDR firewall regions
from firmware config file instead of static defines.

Change-Id: I471e15410ca286d9079a86e3dc3474f66d37b5ab
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
4 files changed