board: Add STM32F769 SoC, discovery board support

Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
diff --git a/board/st/stm32f746-disco/MAINTAINERS b/board/st/stm32f746-disco/MAINTAINERS
index 2df0a65..3bbb513 100644
--- a/board/st/stm32f746-disco/MAINTAINERS
+++ b/board/st/stm32f746-disco/MAINTAINERS
@@ -4,3 +4,4 @@
 F:	board/st/stm32f746-disco
 F:	include/configs/stm32f746-disco.h
 F:	configs/stm32f746-disco_defconfig
+F:	configs/stm32f769-disco_defconfig