feat(stm32mp2): enable DDR driver

Call stm32mp2_ddr_probe() function in platform setup.
Move DDR systematic test file in common.mk.

Change-Id: I982abd33635a3222a52c967eac64676bc26b0d6b
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
diff --git a/plat/st/stm32mp2/bl2_plat_setup.c b/plat/st/stm32mp2/bl2_plat_setup.c
index 20cbc6e..7370a34 100644
--- a/plat/st/stm32mp2/bl2_plat_setup.c
+++ b/plat/st/stm32mp2/bl2_plat_setup.c
@@ -15,6 +15,7 @@
 #include <drivers/mmc.h>
 #include <drivers/st/regulator_fixed.h>
 #include <drivers/st/stm32mp2_ddr_helpers.h>
+#include <drivers/st/stm32mp2_ram.h>
 #include <drivers/st/stm32mp_pmic2.h>
 #include <drivers/st/stm32mp_risab_regs.h>
 #include <lib/fconf/fconf.h>
@@ -135,6 +136,13 @@
 
 void bl2_platform_setup(void)
 {
+	int ret;
+
+	ret = stm32mp2_ddr_probe();
+	if (ret != 0) {
+		ERROR("DDR probe: error %d\n", ret);
+		panic();
+	}
 }
 
 static void reset_backup_domain(void)