stm32cube: Introduce STM32Cube for STM32L0xx series

With this commit we provide header and HAL/LL files for all STM32L0
SoCs.
Using STM32Cube provides generic access to all families, maximizes
code reuse across different STM32 families and helps taking benefit
of a mature SDK

Origin: STM32Cube
URL: http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software/stm32cubel0.html
Purpose: Introduction of STM32L0xx STM32Cube definitions
and Abstraction Layers
Maintained-by: External

Original STM32Cube tree structure has been modified to a minimum
structure for a better fit into Zephyr. hal is split into 2 parts:
-driver: initially Drivers/STM32L0xx_HAL_Driver, contains HAL and LL
-soc: initially Drivers/CMSIS/Device/ST/STM32L0xx, contains stm32l0xx
socs header files

Change-Id: Ibb8ea2e059b5d4f63848be269765d803f842cc2f
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
162 files changed