stm32mp1: add trusted boot with TF-A

Add support of trusted boot, using TF-A as first stage bootloader,
The boot sequence is
  BootRom >=> TF-A.stm32 (clock & DDR) >=> U-Boot.stm32

The TF-A monitor provides secure monitor with support of SMC
- proprietary to manage secure devices (BSEC for example)
- PSCI for power

The same device tree is used for STMicroelectronics boards with
basic boot and with trusted boot.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/clk/clk_stm32mp1.c b/drivers/clk/clk_stm32mp1.c
index aebc6f0..24859fd 100644
--- a/drivers/clk/clk_stm32mp1.c
+++ b/drivers/clk/clk_stm32mp1.c
@@ -15,10 +15,12 @@
 #include <dt-bindings/clock/stm32mp1-clks.h>
 #include <dt-bindings/clock/stm32mp1-clksrc.h>
 
+#ifndef CONFIG_STM32MP1_TRUSTED
 #if !defined(CONFIG_SPL) || defined(CONFIG_SPL_BUILD)
 /* activate clock tree initialization in the driver */
 #define STM32MP1_CLOCK_TREE_INIT
 #endif
+#endif
 
 #define MAX_HSI_HZ		64000000