stm32mp1: Add DDR support and its security with TZC400

The DDR driver is under dual license, BSD and GPLv2.
The configuration parameters are taken from device tree.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>