stm32: add support for stm32f7 & stm32f746 discovery board

This patch adds support for stm32f7 family & stm32f746 board.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
diff --git a/board/st/stm32f746-disco/MAINTAINERS b/board/st/stm32f746-disco/MAINTAINERS
new file mode 100644
index 0000000..2df0a65
--- /dev/null
+++ b/board/st/stm32f746-disco/MAINTAINERS
@@ -0,0 +1,6 @@
+STM32F746 DISCOVERY BOARD
+M:	Vikas Manocha <vikas.manocha@st.com>
+S:	Maintained
+F:	board/st/stm32f746-disco
+F:	include/configs/stm32f746-disco.h
+F:	configs/stm32f746-disco_defconfig