blockingqueue.hpp: Disable priority inheritance for signaling semaphores

The head/tail semaphores are not used as lock but rather as resource
counters and thus relate more as signaling semaphores. Disable PI for
them.

I run my code with CONFIG_DEBUG_ASSERTIONS=y and the kernel panics due
to the semaphore having no holder, disabling PI fixes this.

src/include/containers/BlockingQueue.hpp

@@ -46,6 +46,8 @@ public:
 	{
 		px4_sem_init(&_sem_head, 0, N);
 		px4_sem_init(&_sem_tail, 0, 0);
+		px4_sem_setprotocol(&_sem_head, SEM_PRIO_NONE);
+		px4_sem_setprotocol(&_sem_tail, SEM_PRIO_NONE);
 	}
 
 	~BlockingQueue()