Fix STM32.PWM.
Fix STM32.PWM.

* channels were not enabled after a PWM configuration.
* TIM2 and TIM5 were not being handled.

Fabien-Chouteau/Ada_Drivers_Library,AdaCore/Ada_Drivers_Library,Fabien-Chouteau/Ada_Drivers_Library,AdaCore/Ada_Drivers_Library,ellamosi/Ada_BMP_Library,simonjwright/Ada_Drivers_Library,lambourg/Ada_Drivers_Library,simonjwright/Ada_Drivers_Library