libs/wlgen/rta: Limit task name to 15 characters
Created by: bjackman
rt-app uses pthread_setname_np(3) to set the names of tasks on the target [1]. This interface limits thread name length to 16 characters including the null '\0'.
Although rt-app prints a message on the target, the workload execution goes ahead when the provided task names are too long, and the tasks are named "rt-app". This means they are not found when later examining the trace.
Therefore, raise an exception on the host to prevent this situation arising.