DMA: Handle undefined Chain mode tags

Fixes DT Racer speed issues

pcsx2/Hw.cpp

@@ -399,6 +399,10 @@ bool hwDmacSrcChain(DMACh& dma, int id)
 			dma.madr = dma.tadr + 16;
 			//Don't Increment tadr; breaks Soul Calibur II and III
 			return true;
+		// Undefined Tag handling ends the DMA, maintaining the bad TADR and Tag in upper CHCR
+		// Some games such as DT racer try to use RET tags on IPU, which it doesn't support
+		default:
+			return true;
 	}
 
 	return false;