Removes the dependency of the module riot_freertos from module xtimer. This avoids that xtimer is used even if it is not really needed which in turn occupies the first timer device and tests/periph_timer fails.
Using a mutex for critical section handling with portENTER_CRITICAL and portEXIT_CRITICAL does not work for RIOT, as this function can also be called in the interrupt context. Therefore, the given mutex is not used. Instead, the basic default FreeRTOS mechanism for critical sections is used by simply disabling interrupts. Since context switches for the ESP32 are also based on interrupts, there is no possibility that another thread will enter the critical section once the interrupts are disabled.
xSemaphoreTakeRecursive() returned before the fix: pdFALSE(equal to pdFAIL) when the call was successful in obtaining the semaphore
and pdTRUE(equal to pdPASS) when the call did not successfully obtain the semaphore.
According to freertos documentation:
"pdPASS Returned only if the call to xSemaphoreTakeRecursive() was successful in obtaining the semaphore"
"pdFAIL Returned if the call to xSemaphoreTakeRecursive() did not successfully obtain the semaphore."
Fixed it to return the correct value.
xSemaphoreTake() returned before the fix: pdFALSE(equal to pdFAIL) when the call was successful in obtaining the semaphore
and pdTRUE(equal to pdPASS) when the call did not successfully obtain the semaphore.
According to freertos documentation:
"pdPASS Returned only if the call to xSemaphoreTake() was successful in obtaining the semaphore"
"pdFAIL Returned if the call to xSemaphoreTake() did not successfully obtain the semaphore."
Fixed it to return the correct value.
