STM32: Proper semaphore destruction in NuttX driver

libuavcan_drivers/stm32/driver/include/uavcan_stm32/thread.hpp

@@ -45,12 +45,13 @@ public:
 
 #elif UAVCAN_STM32_NUTTX
 
-class Event
+class Event : uavcan::Noncopyable
 {
     sem_t sem_;
 
 public:
     Event();
+    ~Event();
 
     bool wait(uavcan::MonotonicDuration duration);
 

libuavcan_drivers/stm32/driver/src/uc_stm32_thread.cpp

@@ -62,6 +62,11 @@ Event::Event()
     (void)sem_init(&sem_, 0, 0);
 }
 
+Event::~Event()
+{
+    (void)sem_destroy(&sem_);
+}
+
 bool Event::wait(uavcan::MonotonicDuration duration)
 {
     if (duration.isNegative())