dmaengine: consolidate initialization of cookies

Provide a common function to initialize a channels cookie values.

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>

drivers/dma/dw_dmac.c

@@ -1021,7 +1021,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 		return -EIO;
 	}
 
-	chan->completed_cookie = chan->cookie = 1;
+	dma_cookie_init(chan);
 
 	/*
 	 * NOTE: some controllers may have additional features that we
@@ -1449,7 +1449,7 @@ static int __init dw_probe(struct platform_device *pdev)
 		struct dw_dma_chan	*dwc = &dw->chan[i];
 
 		dwc->chan.device = &dw->dma;
-		dwc->chan.cookie = dwc->chan.completed_cookie = 1;
+		dma_cookie_init(&dwc->chan);
 		if (pdata->chan_allocation_order == CHAN_ALLOCATION_ASCENDING)
 			list_add_tail(&dwc->chan.device_node,
 					&dw->dma.channels);