Publication remove unused instance class member

src/modules/uORB/Publication.cpp

@@ -69,7 +69,8 @@ bool PublicationBase::update(void *data)
 		orb_advert_t handle = nullptr;
 
 		if (_priority > 0) {
-			handle = orb_advertise_multi(_meta, data, &_instance, _priority);
+			int instance;
+			handle = orb_advertise_multi(_meta, data, &instance, _priority);
 
 		} else {
 			handle = orb_advertise(_meta, data);

src/modules/uORB/Publication.hpp

@@ -81,7 +81,6 @@ protected:
 	const struct orb_metadata *_meta;
 	const int _priority;
 
-	int _instance{0};
 	orb_advert_t _handle{nullptr};
 };