hooks: use hook to implement the callbacks

This way we get the version check implemented and save some
code.

spa/include/spa/monitor/monitor.h

@@ -86,6 +86,17 @@ struct spa_monitor_callbacks {
 	int (*event) (void *data, struct spa_event *event);
 };
 
+#define spa_monitor_call(hook,method,version,...)			\
+({									\
+	int __res = 0;							\
+	spa_hook_call_res(hook, struct spa_monitor_callbacks, __res,	\
+				method, version, ##__VA_ARGS__);	\
+	__res;								\
+})
+
+#define spa_monitor_call_info(hook,i)		spa_monitor_call(hook, info, 0, i)
+#define spa_monitor_call_event(hook,e)		spa_monitor_call(hook, event, 0, e)
+
 /**
  * spa_monitor:
  *