TIM8 correctly. Software serial conficted with parallel PWM input. Fixed
crash due to incorrect timerConfig index calculation code.
The crash occurred when capture compare interrupt handlers attempted to
call an invalid callback.
Note: the crash does not affect existing baseflight code since the
formula is OK when using a 2 dimensional array with equal dimensions.
Formula details here:
https://docs.google.com/spreadsheets/d/1UuxnC0VKiprvt1wt3KXffefEWJUb_-ILFLQuP377Anw
The STM32F3DISCOVERY board would crash when setting GPIOA Pin_13 or
Pin_14 to analog mode so they are excluded in the gpio initialisation.
The USART GPIO configuration did not work when using the F10x code. The
USART status and DMA registers are different too.
