DMAENGINE: extend the control command to include an arg

This adds an argument to the DMAengine control function, so that
we can later provide control commands that need some external data
passed in through an argument akin to the ioctl() operation
prototype.

[dan.j.williams@intel.com: fix up some missed conversions]
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index cb1924f..005329d 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -775,7 +775,7 @@
 }
 
 static int fsl_dma_device_control(struct dma_chan *dchan,
-				  enum dma_ctrl_cmd cmd)
+				  enum dma_ctrl_cmd cmd, unsigned long arg)
 {
 	struct fsldma_chan *chan;
 	unsigned long flags;