MAINTAINERS: update ARM STM STM32MP and STM32MP1 BOARD

Add the missing driver and files for mach-stm32mp / stm32mp1 product.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/board/st/stm32mp1/MAINTAINERS b/board/st/stm32mp1/MAINTAINERS
index 3bf4c21..2930947 100644
--- a/board/st/stm32mp1/MAINTAINERS
+++ b/board/st/stm32mp1/MAINTAINERS
@@ -1,9 +1,10 @@
 STM32MP1 BOARD
 M:	Patrick Delaunay <patrick.delaunay@st.com>
 L:	uboot-stm32@st-md-mailman.stormreply.com (moderated for non-subscribers)
+T:	git https://gitlab.denx.de/u-boot/custodians/u-boot-stm.git
 S:	Maintained
-F:	arch/arm/dts/stm32mp157*
-F:	board/st/stm32mp1
+F:	arch/arm/dts/stm32mp15*
+F:	board/st/stm32mp1/
 F:	configs/stm32mp15_basic_defconfig
 F:	configs/stm32mp15_optee_defconfig
 F:	configs/stm32mp15_trusted_defconfig