ARM: sa11x0: fix build errors from DMA engine API updates

The recent merge of the sa11x0 code into mainline had silent conflicts
with further development of the DMA engine API, leading to build errors
and warnings:

drivers/net/irda/sa1100_ir.c: In function 'sa1100_irda_dma_start':
drivers/net/irda/sa1100_ir.c:151: error: too few arguments to function 'chan->device->device_prep_slave_sg'
drivers/dma/sa11x0-dma.c: In function 'sa11x0_dma_probe':
drivers/dma/sa11x0-dma.c:950: warning: assignment from incompatible pointer type

Fix these.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/net/irda/sa1100_ir.c b/drivers/net/irda/sa1100_ir.c
index a0d1913..e250675 100644
--- a/drivers/net/irda/sa1100_ir.c
+++ b/drivers/net/irda/sa1100_ir.c
@@ -147,7 +147,7 @@
 	struct dma_async_tx_descriptor *desc;
 	struct dma_chan *chan = buf->chan;
 
-	desc = chan->device->device_prep_slave_sg(chan, &buf->sg, 1, dir,
+	desc = dmaengine_prep_slave_sg(chan, &buf->sg, 1, dir,
 			DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (desc) {
 		desc->callback = cb;