stm32f1: Enable STM32Cube SDK support on stm32f1 family

Create HAS_CUBE config flag to control activation of STM32Cube support.
Generate fitting compilation options for STM32Cube in
/ext/hal/stm32cube/Makefile soc.h is updated to include minimum include
files from ext/hal/stm23cube

Change-Id: If58ce0a4fdb7fbf5f171dfe5f1f8eb75126a8313
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>