feat(stm32mp1): introduce new flag for STM32MP13

STM32MP13 is a variant of STM32MP1, with a single Cortex-A7, and no
Cortex-M4.
There is only one DDR port.
SP_min is not supported, only OP-TEE can be used as monitor.
STM32MP13 uses the header v2.0 format for stm32image generation
for BL2.

Change-Id: Ie5b0e3230c5e064fe96f3561fc5b3208914dea53
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/plat/st/stm32mp1/sp_min/sp_min-stm32mp1.mk b/plat/st/stm32mp1/sp_min/sp_min-stm32mp1.mk
index b506e95..c3fc2cb 100644
--- a/plat/st/stm32mp1/sp_min/sp_min-stm32mp1.mk
+++ b/plat/st/stm32mp1/sp_min/sp_min-stm32mp1.mk
@@ -4,6 +4,10 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
+ifeq ($(STM32MP13),1)
+$(error "SP_min is not supported on STM32MP13 platform")
+endif
+
 SP_MIN_WITH_SECURE_FIQ	:=	1
 
 ifneq ($(STM32MP_USE_STM32IMAGE),1)