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/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
index 2a6429d..ea4c8d5 100644
--- a/drivers/spi/spi-topcliff-pch.c
+++ b/drivers/spi/spi-topcliff-pch.c
@@ -1078,7 +1078,7 @@
 		sg_dma_address(sg) = dma->rx_buf_dma + sg->offset;
 	}
 	sg = dma->sg_rx_p;
-	desc_rx = dma->chan_rx->device->device_prep_slave_sg(dma->chan_rx, sg,
+	desc_rx = dmaengine_prep_slave_sg(dma->chan_rx, sg,
 					num, DMA_DEV_TO_MEM,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!desc_rx) {
@@ -1123,7 +1123,7 @@
 		sg_dma_address(sg) = dma->tx_buf_dma + sg->offset;
 	}
 	sg = dma->sg_tx_p;
-	desc_tx = dma->chan_tx->device->device_prep_slave_sg(dma->chan_tx,
+	desc_tx = dmaengine_prep_slave_sg(dma->chan_tx,
 					sg, num, DMA_MEM_TO_DEV,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!desc_tx) {