arm: stm32mp: add choice for STM32MP SOC family

Add mandatory choice for SOC support in ARCH_STM32MP.

This patch is a preliminary step for new SOC introduction
in STM32MP family.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/configs/stm32mp15_defconfig b/configs/stm32mp15_defconfig
index a6398c7..f8f9806 100644
--- a/configs/stm32mp15_defconfig
+++ b/configs/stm32mp15_defconfig
@@ -6,11 +6,11 @@
 CONFIG_ENV_SECT_SIZE=0x40000
 CONFIG_DEFAULT_DEVICE_TREE="stm32mp157c-ev1"
 CONFIG_TARGET_ST_STM32MP15x=y
+CONFIG_TYPEC_STUSB160X=y
+CONFIG_ENV_OFFSET_REDUND=0x4C0000
 CONFIG_DDR_CACHEABLE_SIZE=0x10000000
 CONFIG_CMD_STM32KEY=y
 CONFIG_CMD_STM32PROG=y
-CONFIG_ENV_OFFSET_REDUND=0x4C0000
-CONFIG_TYPEC_STUSB160X=y
 # CONFIG_ARMV7_NONSEC is not set
 CONFIG_SYS_LOAD_ADDR=0xc2000000
 CONFIG_SYS_MEMTEST_START=0xc0000000