drivers: pwm: stm32: refactor driver using LL API

The PWM drivers has been refactored using the HAL LL API. Not only that,
but the set pin_set function is now faster, as channel output compare is
just initialized if needed.

NOTE: Has been tested using H743zi board for now.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
17 files changed