stm32mp1: add minimal support for co-processor Cortex-M4

STM32MP1 chip embeds a dual Cortex-A7 and a Cortex-M4.
The support for Cortex-M4 clocks is added when configuring the clock tree.
Some minimal security features to allow communications between A7 and M4
are also added.

Change-Id: I60417e244a476f60a2758f4969700b2684056665
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/include/drivers/st/stm32mp1_clk.h b/include/drivers/st/stm32mp1_clk.h
index 1e0d949..7afa5ad 100644
--- a/include/drivers/st/stm32mp1_clk.h
+++ b/include/drivers/st/stm32mp1_clk.h
@@ -13,6 +13,7 @@
 int stm32mp1_clk_init(void);
 
 bool stm32mp1_rcc_is_secure(void);
+bool stm32mp1_rcc_is_mckprot(void);
 
 void __stm32mp1_clk_enable(unsigned long id, bool caller_is_secure);
 void __stm32mp1_clk_disable(unsigned long id, bool caller_is_secure);