Set TIM_OCMODE_INACTIVE when mode TIMER_OUTPUT_COMPARE_INACTIVE is selected

Fixes stm32duino#692

Author: ABOSTM

cores/arduino/HardwareTimer.cpp

@@ -414,7 +414,7 @@ void HardwareTimer::setMode(uint32_t channel, TimerModes_t mode, PinName pin)
  _channelIC[channel - 1].ICPolarity = TIMER_NOT_USED;
  break;
  case TIMER_OUTPUT_COMPARE_INACTIVE:
- _channelOC[channel - 1].OCMode = TIM_OCMODE_ACTIVE;
+ _channelOC[channel - 1].OCMode = TIM_OCMODE_INACTIVE;
  _channelIC[channel - 1].ICPolarity = TIMER_NOT_USED;
  break;
  case TIMER_OUTPUT_COMPARE_TOGGLE: