ext: stm32cube: update stm32f1xx cube version

Update Cube version for STM32F1XX family
from version: V1.14.0
to version: V1.15.0

Add support for Low Level API on stm32f1 family

Change-Id: I8cb5fe2fd94be3a320e863c7b5ed59e4c2312e87
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
147 files changed