fdts: stm32mp1: add bsec node ...

This node is added in a new file stm32mp157c-security.dtsi.
This node includes OTPs that should be shadowed and made readable
to non secure world.
Explicitly add status and secure-status, as these OTPs are accessible
by secure and non-secure world.

The stgen node is also moved to this file.

Change-Id: I3c89a01588d2e411fecfc44997e1c5df2fc37cad
Signed-off-by: Yann Gautier <yann.gautier@st.com>

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>

stm32mp1: introduce STM32MP1 discovery boards ...

Add the device tree files to support the 2 discovery boards: DK1 & DK2.

Change-Id: I90b4797dc69bd0aab1b643a72c932ead48a03c1f
Signed-off-by: Yann Gautier <yann.gautier@st.com>