doc: Add documentation for STM32 MCUs

Add documentation for STM32 MCUs (F4, F7 and H7 series).

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/board/st/stm32f429-evaluation/MAINTAINERS b/board/st/stm32f429-evaluation/MAINTAINERS
index 29d00ef..b272893 100644
--- a/board/st/stm32f429-evaluation/MAINTAINERS
+++ b/board/st/stm32f429-evaluation/MAINTAINERS
@@ -1,6 +1,7 @@
 STM32F429-EVALUATION BOARD
 M:	Patrice Chotard <patrice.chotard@foss.st.com>
 S:	Maintained
+F:	doc/board/st/
 F:	board/st/stm32f429-evaluation/
 F:	include/configs/stm32f429-evaluation.h
 F:	configs/stm32f429-evaluation_defconfig