stm32mp1: Add chip ID

Add STM32MP1_CHIP_ID define used to identify the STM32MP15x SOC.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Change-Id: I6085577fde3606b87d55fc35533c41d3b12b877d
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/177371


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: Yann GAUTIER <yann.gautier@st.com>
Tested-by: Yann GAUTIER <yann.gautier@st.com>

plat/st/stm32mp1/stm32mp1_def.h

@@ -31,6 +31,8 @@
 /*******************************************************************************
  * CHIP ID
  ******************************************************************************/
+#define STM32MP1_CHIP_ID	U(0x500)
+
 #define STM32MP157C_PART_NB	U(0x05000000)
 #define STM32MP157A_PART_NB	U(0x05000001)
 #define STM32MP153C_PART_NB	U(0x05000024)