dmaengine: at_hdmac: remove unsuded atc_cleanup_descriptors()

Since patch 7c407d3e54dcc0c79119553c8d5ef176c1d5bc3a (DMA: AT91:
Get residual bytes in dma buffer), the function
atc_cleanup_descriptors() is not used anymore. We remove it to prevent
warnings.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

drivers/dma/at_hdmac.c

@@ -416,37 +416,6 @@ static void atc_complete_all(struct at_dma_chan *atchan)
 		atc_chain_complete(atchan, desc);
 }
 
-/**
- * atc_cleanup_descriptors - cleanup up finished descriptors in active_list
- * @atchan: channel to be cleaned up
- *
- * Called with atchan->lock held and bh disabled
- */
-static void atc_cleanup_descriptors(struct at_dma_chan *atchan)
-{
-	struct at_desc	*desc, *_desc;
-	struct at_desc	*child;
-
-	dev_vdbg(chan2dev(&atchan->chan_common), "cleanup descriptors\n");
-
-	list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
-		if (!(desc->lli.ctrla & ATC_DONE))
-			/* This one is currently in progress */
-			return;
-
-		list_for_each_entry(child, &desc->tx_list, desc_node)
-			if (!(child->lli.ctrla & ATC_DONE))
-				/* Currently in progress */
-				return;
-
-		/*
-		 * No descriptors so far seem to be in progress, i.e.
-		 * this chain must be done.
-		 */
-		atc_chain_complete(atchan, desc);
-	}
-}
-
 /**
  * atc_advance_work - at the end of a transaction, move forward
  * @atchan: channel where the transaction ended