stm32mp1: Add BL32 SP_min secure monitor

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Mathieu Belou <mathieu.belou@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
diff --git a/plat/st/stm32mp1/include/platform_def.h b/plat/st/stm32mp1/include/platform_def.h
index 9c148ad..47e1ffc 100644
--- a/plat/st/stm32mp1/include/platform_def.h
+++ b/plat/st/stm32mp1/include/platform_def.h
@@ -18,7 +18,11 @@
  ******************************************************************************/
 
 /* Size of cacheable stacks */
+#if defined(IMAGE_BL32)
+#define PLATFORM_STACK_SIZE		0x600
+#else
 #define PLATFORM_STACK_SIZE		0xC00
+#endif
 
 /* SSBL = second stage boot loader */
 #define BL33_IMAGE_NAME			"ssbl"