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_tx.c b/crypto/async_tx/async_tx.c
index f39777f..56288218 100644
--- a/crypto/async_tx/async_tx.c
+++ b/crypto/async_tx/async_tx.c
@@ -361,13 +361,13 @@
 }
 
 /**
- * async_tx_find_channel - find a channel to carry out the operation or let
+ * __async_tx_find_channel - find a channel to carry out the operation or let
  *	the transaction execute synchronously
  * @depend_tx: transaction dependency
  * @tx_type: transaction type
  */
 struct dma_chan *
-async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx,
+__async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx,
 	enum dma_transaction_type tx_type)
 {
 	/* see if we can keep the chain on one channel */
@@ -383,7 +383,7 @@
 	} else
 		return NULL;
 }
-EXPORT_SYMBOL_GPL(async_tx_find_channel);
+EXPORT_SYMBOL_GPL(__async_tx_find_channel);
 #else
 static int __init async_tx_init(void)
 {