Properly return success in sceKernelWakeupThread().

Fixes #1596, fixes #1796, possibly others.  I can't believe how long
I stared at this code and debugged it without noticing such a simple
thing...

Core/HLE/sceKernelThread.cpp

@@ -2349,6 +2349,7 @@ void sceKernelWakeupThread()
 			VERBOSE_LOG(HLE,"sceKernelWakeupThread(%i) - woke thread at %i", uid, t->nt.wakeupCount);
 			__KernelResumeThreadFromWait(uid);
 			hleReSchedule("thread woken up");
+			RETURN(0);
 		}
 	} 
 	else {