v10.4.6

FreeRTOS 10.4.6

Updates and bugfixes:
- Updated osSemaphoreGetCount to use uxSemaphoreGetCountFromISR instead of uxQueueMessagesWaitingFromISR
- Correct typecasting of argument usStackDepth for xTaskCreate in function osThreadNew (#51)
- Fix mutex allocation for Arm Standard C library and allow it only when the kernel is running