feat(stm32mp2): generate stm32 file

To be able to boot, STM32MPU platforms require the BL2 binary (together
with its DT) to be preceded with an STM32 header. Add the required
files and macro to properly generate this header.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I675de2c5cb733fe9d9e9baf76a941741a06dfac8
diff --git a/plat/st/stm32mp2/platform.mk b/plat/st/stm32mp2/platform.mk
index ba6ab4b..6ea4638 100644
--- a/plat/st/stm32mp2/platform.mk
+++ b/plat/st/stm32mp2/platform.mk
@@ -26,6 +26,15 @@
 # such as metadata (2) and fsbl-m (2) to find all the FIP partitions (default is 2).
 PLAT_PARTITION_MAX_ENTRIES	:=	$(shell echo $$(($(STM32_TF_A_COPIES) + 6)))
 
+# Device tree
+BL2_DTSI			:=	stm32mp25-bl2.dtsi
+FDT_SOURCES			:=	$(addprefix ${BUILD_PLAT}/fdts/, $(patsubst %.dtb,%-bl2.dts,$(DTB_FILE_NAME)))
+
+# Macros and rules to build TF binary
+STM32_TF_STM32			:=	$(addprefix ${BUILD_PLAT}/tf-a-, $(patsubst %.dtb,%.stm32,$(DTB_FILE_NAME)))
+STM32_LD_FILE			:=	plat/st/stm32mp2/${ARCH}/stm32mp2.ld.S
+STM32_BINARY_MAPPING		:=	plat/st/stm32mp2/${ARCH}/stm32mp2.S
+
 # STM32MP2x is based on Cortex-A35, which is Armv8.0, and does not support BTI
 # Disable mbranch-protection to avoid adding useless code
 TF_CFLAGS			+=	-mbranch-protection=none