stm32mp1: update device tree files

The drivers are also updated to reflect the changes.
Set RCC as non-secure.

Change-Id: I568fa1f418355830ad1d4d1cdcdb910fb362231b
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/drivers/st/ddr/stm32mp1_ddr.c b/drivers/st/ddr/stm32mp1_ddr.c
index e109e87..9a50546 100644
--- a/drivers/st/ddr/stm32mp1_ddr.c
+++ b/drivers/st/ddr/stm32mp1_ddr.c
@@ -707,7 +707,7 @@
 	}
 
 	VERBOSE("name = %s\n", config->info.name);
-	VERBOSE("speed = %d MHz\n", config->info.speed);
+	VERBOSE("speed = %d kHz\n", config->info.speed);
 	VERBOSE("size  = 0x%x\n", config->info.size);
 
 	/* DDR INIT SEQUENCE */