stm32mp1: use stm32mp_get_ddr_ns_size() function

Instead of using dt_get_ddr_size() and withdrawing the secure and shared
memory areas, use stm32mp_get_ddr_ns_size() function.

Change-Id: I5608fd7873589ea0e1262ba7d2ee3e52b53d9a7d
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/plat/st/stm32mp1/bl2_plat_setup.c b/plat/st/stm32mp1/bl2_plat_setup.c
index bb9582c..652765c 100644
--- a/plat/st/stm32mp1/bl2_plat_setup.c
+++ b/plat/st/stm32mp1/bl2_plat_setup.c
@@ -353,8 +353,7 @@
 		paged_mem_params = get_bl_mem_params_node(BL32_EXTRA2_IMAGE_ID);
 		assert(paged_mem_params != NULL);
 		paged_mem_params->image_info.image_base = STM32MP_DDR_BASE +
-			(dt_get_ddr_size() - STM32MP_DDR_S_SIZE -
-			 STM32MP_DDR_SHMEM_SIZE);
+			stm32mp_get_ddr_ns_size();
 		paged_mem_params->image_info.image_max_size =
 			STM32MP_DDR_S_SIZE;