stm32mp1: activate OF_BOARD_SETUP and FDT_FIXUP_PARTITIONS

Update kernel MTD partition in device tree with U-Boot information.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index 7f6e805..9dc3c4d 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -38,6 +38,7 @@
 	select CPU_V7A
 	select CPU_V7_HAS_NONSEC if !STM32MP1_TRUSTED
 	select CPU_V7_HAS_VIRT
+	select OF_BOARD_SETUP
 	select PINCTRL_STM32
 	select STM32_RCC
 	select STM32_RESET