Add a "secure" version of STM32 boards based on SCMI when RCC_TZCR.TZEN=1.
Only boards provided by STMicroelectronics are concerned:
-STM32MP157A-DK1
-STM32MP157C-DK2
-STM32MP157C-ED1
-STM32MP157C-EV1
The resources secured by RCC_TZCR.TZEN=1 are managed by OP-TEE
and the associated SCMI services, reset and clock.
These device trees are only supported with stm32mp15_defconfig,
with OP-TEE, SCMI and without SPL support.
Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
