dmaengine: at_hdmac: set residue as total len in atc_tx_status

If transfer status is !=DMA_SUCCESS, return total transfer len as residue,
instead of zero.

Idea from dw_dmac patch by Viresh Kumar.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/at_hdmac.c

@@ -1026,7 +1026,12 @@ atc_tx_status(struct dma_chan *chan,
 
 	spin_unlock_bh(&atchan->lock);
 
-	dma_set_tx_state(txstate, last_complete, last_used, 0);
+	if (ret != DMA_SUCCESS)
+		dma_set_tx_state(txstate, last_complete, last_used,
+			atc_first_active(atchan)->len);
+	else
+		dma_set_tx_state(txstate, last_complete, last_used, 0);
+
 	dev_vdbg(chan2dev(chan), "tx_status: %d (d%d, u%d)\n",
 		 cookie, last_complete ? last_complete : 0,
 		 last_used ? last_used : 0);