dmaengine/dma_slave: introduce inline wrappers

Add inline wrappers for device_prep_slave_sg() and device_prep_dma_cyclic()
interfaces to hide new parameter from current users of affected interfaces.
Convert current users to use new wrappers instead of direct calls.
Suggested by Russell King [https://lkml.org/lkml/2012/2/3/269].

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/drivers/video/mx3fb.c b/drivers/video/mx3fb.c
index 727a514..eec0d7b 100644
--- a/drivers/video/mx3fb.c
+++ b/drivers/video/mx3fb.c
@@ -337,7 +337,7 @@
 
 	/* This enables the channel */
 	if (mx3_fbi->cookie < 0) {
-		mx3_fbi->txd = dma_chan->device->device_prep_slave_sg(dma_chan,
+		mx3_fbi->txd = dmaengine_prep_slave_sg(dma_chan,
 		      &mx3_fbi->sg[0], 1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
 		if (!mx3_fbi->txd) {
 			dev_err(mx3fb->dev, "Cannot allocate descriptor on %d\n",
@@ -1091,7 +1091,7 @@
 	if (mx3_fbi->txd)
 		async_tx_ack(mx3_fbi->txd);
 
-	txd = dma_chan->device->device_prep_slave_sg(dma_chan, sg +
+	txd = dmaengine_prep_slave_sg(dma_chan, sg +
 		mx3_fbi->cur_ipu_buf, 1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
 	if (!txd) {
 		dev_err(fbi->device,