SPU: Use waitable atomics for SPU channels interface

Utilities/Thread.cpp

@@ -1892,6 +1892,7 @@ void thread_base::initialize(void (*error_cb)(), bool(*wait_cb)(const void*))
 
 void thread_base::notify_abort() noexcept
 {
+	m_signal.try_inc();
 	atomic_storage_futex::raw_notify(+m_state_notifier);
 }
 

Utilities/Thread.h

@@ -210,6 +210,12 @@ public:
 		static_cast<thread_base&>(thread).notify();
 	}
 
+	template <typename T>
+	static void raw_notify(named_thread<T>& thread)
+	{
+		static_cast<thread_base&>(thread).notify_abort();
+	}
+
 	// Read current state
 	static inline thread_state state()
 	{