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/shdma.c b/drivers/dma/shdma.c
index 98f82cd..e9de1d3 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -580,7 +580,8 @@
 			       direction, flags);
 }
 
-static int sh_dmae_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd)
+static int sh_dmae_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			   unsigned long arg)
 {
 	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);