dmaengine: fix sparse warning

include/linux/dmaengine.h:364:2: warning: returning void-valued expression

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index acbb364..261e43a4 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -366,7 +366,7 @@
  */
 static inline void dma_async_issue_pending(struct dma_chan *chan)
 {
-	return chan->device->device_issue_pending(chan);
+	chan->device->device_issue_pending(chan);
 }
 
 #define dma_async_memcpy_issue_pending(chan) dma_async_issue_pending(chan)