Merge pull request #4646 from bulislaw/fix_rtx_mutex

RTX: Fixed RTXv5 mutex owner list handling.

Author: theotherjimmy

rtos/rtx5/TARGET_CORTEX_M/rtx_mutex.c

@@ -187,6 +187,9 @@ osStatus_t svcRtxMutexAcquire (osMutexId_t mutex_id, uint32_t timeout) {
     mutex->owner_thread = runnig_thread;
     mutex->owner_next   = runnig_thread->mutex_list;
     mutex->owner_prev   = NULL;
+    if (runnig_thread->mutex_list != NULL) {
+        runnig_thread->mutex_list->owner_prev = mutex;
+    }
     runnig_thread->mutex_list = mutex;
     mutex->lock = 1U;
     EvrRtxMutexAcquired(mutex, mutex->lock);