In the stm32f4 family, mipi dsi is only supported on stm32f469.
So add a new stm32f469 dtsi file & add mipi dsi support inside.
Signed-off-by: NPhilippe Cornu <philippe.cornu@st.com>
Signed-off-by: NAlexandre Torgue <alexandre.torgue@st.com>