feat(stm32mp2): add helper to get DDRDBG base address

Add a function to get DDRDBG peripheral IO memory base address.

Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Change-Id: I20d14fca49528c296c1f7d49a66129d932f44e49
diff --git a/plat/st/stm32mp2/stm32mp2_private.c b/plat/st/stm32mp2/stm32mp2_private.c
index 99f6be2..d33fa0b 100644
--- a/plat/st/stm32mp2/stm32mp2_private.c
+++ b/plat/st/stm32mp2/stm32mp2_private.c
@@ -281,3 +281,8 @@
 {
 	return tamp_bkpr(BKPR_BOOT_MODE);
 }
+
+uintptr_t stm32_ddrdbg_get_base(void)
+{
+	return DDRDBG_BASE;
+}