ARM: dts: stm32: convert stm32mp2 board to OF_UPSTREAM

Enable OF_UPSTREAM flag for STM32MP2 platforms.
Add fixed-clock ck_flexgen_08 and ck_icn_ls_mcu until STM32MP25
clock driver will be available.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index ad92520..5825090 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -96,6 +96,7 @@
 	imply CMD_NVEDIT_INFO
 	imply DM_REGULATOR
 	imply DM_REGULATOR_SCMI
+	imply OF_UPSTREAM
 	imply OPTEE
 	imply RESET_SCMI
 	imply SYSRESET_PSCI