dmaengine: consolidate assignment of DMA cookies

Everyone deals with assigning DMA cookies in the same way (it's part of
the API so they should be), so lets consolidate the common code into a
helper function to avoid this duplication.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
[imx-sdma.c & mxs-dma.c]
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/drivers/dma/ppc4xx/adma.c b/drivers/dma/ppc4xx/adma.c
index 40082ec..12e94dd 100644
--- a/drivers/dma/ppc4xx/adma.c
+++ b/drivers/dma/ppc4xx/adma.c
@@ -2151,22 +2151,6 @@
 }
 
 /**
- * ppc440spe_desc_assign_cookie - assign a cookie
- */
-static dma_cookie_t ppc440spe_desc_assign_cookie(
-		struct ppc440spe_adma_chan *chan,
-		struct ppc440spe_adma_desc_slot *desc)
-{
-	dma_cookie_t cookie = chan->common.cookie;
-
-	cookie++;
-	if (cookie < 0)
-		cookie = 1;
-	chan->common.cookie = desc->async_tx.cookie = cookie;
-	return cookie;
-}
-
-/**
  * ppc440spe_rxor_set_region_data -
  */
 static void ppc440spe_rxor_set_region(struct ppc440spe_adma_desc_slot *desc,
@@ -2236,8 +2220,7 @@
 	slots_per_op = group_start->slots_per_op;
 
 	spin_lock_bh(&chan->lock);
-
-	cookie = ppc440spe_desc_assign_cookie(chan, sw_desc);
+	cookie = dma_cookie_assign(tx);
 
 	if (unlikely(list_empty(&chan->chain))) {
 		/* first peer */