Add bindings that will be used to define DDR regions
and their access rights.

Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Change-Id: I745a7e580ef2b9e251d53db12c5a0a86dfe34463
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/178512


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: Yann GAUTIER <yann.gautier@st.com>