arm: stm32: add new architecture for STM32MP family

- add new arch stm32mp for STM32 MPU/Soc based on Cortex A
- support for stm32mp157 SOC
- SPL is used as first boot stage loader
- using driver model for all the drivers, even in SPL
- all security feature are deactivated (ETZC and TZC)
- reused STM32 MCU drivers when it is possible

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index f251cf7..c4f10aa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -195,6 +195,11 @@
 F:	arch/arm/cpu/arm926ejs/spear/
 F:	arch/arm/include/asm/arch-spear/
 
+ARM STM STM32MP
+M:	Patrick Delaunay <patrick.delaunay@st.com>
+S:	Maintained
+F:	arch/arm/mach-stm32mp
+
 ARM STM STV0991
 M:	Vikas Manocha <vikas.manocha@st.com>
 S:	Maintained