plat-stm32mp2: update reset and clocks driver flags for STM32MP21

Add CFG_STM32MP21_CLK and CFG_STM32MP21_RSTCTRL flags to enable
RCC drivers.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
Reviewed-by: Etienne Carriere <etienne.carriere@foss.st.com>
Acked-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
diff --git a/core/arch/arm/plat-stm32mp2/conf.mk b/core/arch/arm/plat-stm32mp2/conf.mk
index 1b444d4..5b18b32 100644
--- a/core/arch/arm/plat-stm32mp2/conf.mk
+++ b/core/arch/arm/plat-stm32mp2/conf.mk
@@ -53,6 +53,8 @@
 $(call force,CFG_WITH_LPAE,y)
 
 ifeq ($(CFG_STM32MP21),y)
+$(call force,CFG_STM32MP21_CLK,y)
+$(call force,CFG_STM32MP21_RSTCTRL,y)
 else
 $(call force,CFG_STM32MP25_CLK,y)
 $(call force,CFG_STM32MP25_RSTCTRL,y)