Tracing: Incorrect Unlock Mutex Trace Hook Fix

Changed location of the last k_mutex_unlock trace hook since it was
being called after k_sched_unlock, which could result in tracing
scenarios (other thread waiting for lock) where it appeared that a
mutex was being locked again before becoming unlocked.

Signed-off-by: Torbjörn Leksell <torbjorn.leksell@percepio.com>

kernel/mutex.c

@@ -264,10 +264,10 @@ int z_impl_k_mutex_unlock(struct k_mutex *mutex)
 
 
 k_mutex_unlock_return:
-	k_sched_unlock();
-
 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, unlock, mutex, 0);
 
+	k_sched_unlock();
+
 	return 0;
 }