STM32H7 timers

I noticed that for the STM32H7 family, TIM9, TIM10, TIM11 are referenced in stm32_tim_lowerhalf.c and stm32_tickless.c (probably in other files such as kconfig as well) even though they don't exist for this chip.

This is partly my fault since I copied the stm32_tim_lowerhalf.c from the STM32F7 family and created the pull request about a year ago. Has anybody noticed and correct this already? Otherwise I will work on this and create a pull request.

Start by inspecting stm32_tim_lowerhalf.c and stm32_tickless.c, then search the repository for STM32H7 references to TIM9, TIM10, and TIM11, including Kconfig files. Done means these nonexistent timers are no longer referenced in the STM32H7 configuration or timer code.

Written by the indexing model from the issue text.