uORBManager.cpp: Change how old / stale semaphore handles are used

When the semaphore is released and re-instantiated, do proper cleanup
in g_sem_pool.reserve(). Also remove GlobalSemPool and GlobalLock::set
and replace them with free() which just destroys the mutex.

platforms/common/uORB/uORBManager.cpp

@@ -443,8 +443,7 @@ int uORB::Manager::orb_poll(orb_poll_struct_t *fds, unsigned int nfds, int timeo
 		}
 	}
 
-	// recover from releasing multiple times
-	g_sem_pool.set(lock_idx, 0);
+	// release the semaphore
 	g_sem_pool.free(lock_idx);
 
 	return err ? -1 : count;
@@ -518,6 +517,7 @@ void uORB::Manager::GlobalSemPool::free(int8_t i)
 {
 	lock();
 
+	_global_sem[i].free();
 	_global_sem[i].in_use = false;
 
 	unlock();
@@ -543,6 +543,9 @@ int8_t uORB::Manager::GlobalSemPool::reserve()
 		return -1;
 	}
 
+	// Make sure the semaphore is initialized properly for the new user
+	_global_sem[i].init();
+
 	// Mark this one as in use
 	_global_sem[i].in_use = true;
 

platforms/common/uORB/uORBManager.hpp

@@ -634,7 +634,6 @@ class Manager
 		int8_t reserve();
 		void free(int8_t i);
 
-		void set(int8_t i, int val) {_global_sem[i].set(val);}
 		void take(int8_t i) { do {} while (_global_sem[i].take() != 0); }
 		int take_interruptible(int8_t i) { return _global_sem[i].take(); }
 		int take_timedwait(int8_t i, struct timespec *abstime) { return _global_sem[i].take_timedwait(abstime); }
@@ -658,18 +657,12 @@ class Manager
 				sem_setprotocol(&_lock, SEM_PRIO_NONE);
 #endif
 				in_use = false;
+				_callback_ptr = nullptr;
 			}
-			void set(int val)
-			{
-				px4_sem_destroy(&_sem);
-				px4_sem_init(&_sem, 1, val);
-#if __PX4_NUTTX
-				sem_setprotocol(&_sem, SEM_PRIO_NONE);
-#endif
-			}
-			int take() {return px4_sem_wait(&_sem);}
+			void free() { px4_sem_destroy(&_sem); }
+			int take() { return px4_sem_wait(&_sem); }
 			int take_timedwait(struct timespec *abstime) { return px4_sem_timedwait(&_sem, abstime); }
-			void release() {px4_sem_post(&_sem); }
+			void release() { px4_sem_post(&_sem); }
 			int value() { int value; px4_sem_getvalue(&_sem, &value); return value; }
 			bool in_use{false};