drivers/clock_control: stm32 fix struct wrongly dereferenced

This commit fixes several occurences where a struct members is wrongly
dereferenced, which causes a compile error in case the msi clock is used
as system clock.
Only affects stm32wb and stm32wl with MSI selected as sysclock.

Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>
1 file changed