Don't block a null enqueue if already empty.

Core/HLE/__sceAudio.cpp

@@ -155,7 +155,7 @@ u32 __AudioEnqueue(AudioChannel &chan, int chanNum, bool blocking) {
 
 	// If there's anything on the queue at all, it should be busy, but we try to be a bit lax.
 	//if (chan.sampleQueue.size() > chan.sampleCount * 2 * chanQueueMaxSizeFactor || chan.sampleAddress == 0) {
-	if (chan.sampleQueue.size() > 0 || chan.sampleAddress == 0) {
+	if (chan.sampleQueue.size() > 0) {
 		if (blocking) {
 			// TODO: Regular multichannel audio seems to block for 64 samples less?  Or enqueue the first 64 sync?
 			int blockSamples = (int)chan.sampleQueue.size() / 2 / chanQueueMinSizeFactor;