spl: stm32f7: add kernel boot support

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
diff --git a/arch/arm/mach-stm32/Kconfig b/arch/arm/mach-stm32/Kconfig
index a3390d0..101089d 100644
--- a/arch/arm/mach-stm32/Kconfig
+++ b/arch/arm/mach-stm32/Kconfig
@@ -21,6 +21,7 @@
 	select SPL_OF_CONTROL
 	select SPL_OF_LIBFDT
 	select SPL_OF_TRANSLATE
+	select SPL_OS_BOOT
 	select SPL_PINCTRL
 	select SPL_RAM
 	select SPL_SERIAL_SUPPORT