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/usb/musb/ux500_dma.c b/drivers/usb/musb/ux500_dma.c
index 2a36bf3..d05c7fb 100644
--- a/drivers/usb/musb/ux500_dma.c
+++ b/drivers/usb/musb/ux500_dma.c
@@ -120,8 +120,7 @@
 	dma_chan->device->device_control(dma_chan, DMA_SLAVE_CONFIG,
 					     (unsigned long) &slave_conf);
 
-	dma_desc = dma_chan->device->
-			device_prep_slave_sg(dma_chan, &sg, 1, direction,
+	dma_desc = dmaengine_prep_slave_sg(dma_chan, &sg, 1, direction,
 					     DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!dma_desc)
 		return false;