Use the DDR3 dtsi files generated by STM32CubeMX 5.6.0
Speed Bin Grade = using DDR3-1066G / 8-8-8 and all others
parameters at default value.
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>