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>
diff --git a/drivers/dma/txx9dmac.c b/drivers/dma/txx9dmac.c
index bb7b3d9..40440f9 100644
--- a/drivers/dma/txx9dmac.c
+++ b/drivers/dma/txx9dmac.c
@@ -1034,7 +1034,7 @@
 		return -EIO;
 	}
 
-	chan->completed_cookie = chan->cookie = 1;
+	dma_cookie_init(chan);
 
 	dc->ccr = TXX9_DMA_CCR_IMMCHN | TXX9_DMA_CCR_INTENE | CCR_LE;
 	txx9dmac_chan_set_SMPCHN(dc);
@@ -1163,7 +1163,7 @@
 	dc->ddev->chan[ch] = dc;
 	dc->chan.device = &dc->dma;
 	list_add_tail(&dc->chan.device_node, &dc->chan.device->channels);
-	dc->chan.cookie = dc->chan.completed_cookie = 1;
+	dma_cookie_init(&dc->chan);
 
 	if (is_dmac64(dc))
 		dc->ch_regs = &__txx9dmac_regs(dc->ddev)->CHAN[ch];