configs: stm32mp1: move SUPPORT_SPL in STM32MP15x

The SPL is only supported by STM32MP15x not by all the
SOC with STM32MP arch.
Only TFABOOT is supported in next products.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2f8c793..e0488fd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1956,7 +1956,6 @@
 	select OF_SYSTEM_SETUP
 	select PINCTRL
 	select REGMAP
-	select SUPPORT_SPL
 	select SYSCON
 	select SYSRESET
 	select SYS_THUMB_BUILD
diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index e48f98b..be0d74b 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -46,6 +46,7 @@
 	select STM32_RCC
 	select STM32_RESET
 	select STM32_SERIAL
+	select SUPPORT_SPL
 	select SYS_ARCH_TIMER
 	imply CMD_NVEDIT_INFO
 	help