async_tx: allow architecture specific async_tx_find_channel implementations

The source and destination addresses are included to allow channel
selection based on address alignment.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/crypto/async_tx/async_memset.c b/crypto/async_tx/async_memset.c
index 8e98ab0..09c0e83 100644
--- a/crypto/async_tx/async_memset.c
+++ b/crypto/async_tx/async_memset.c
@@ -46,7 +46,8 @@
 	struct dma_async_tx_descriptor *depend_tx,
 	dma_async_tx_callback cb_fn, void *cb_param)
 {
-	struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMSET);
+	struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMSET,
+						      &dest, 1, NULL, 0, len);
 	struct dma_device *device = chan ? chan->device : NULL;
 	struct dma_async_tx_descriptor *tx = NULL;