DMA: AT91: Get transfer width

In one dma transfer, the data transfer width can be configured and it is limited by source or destination peripheral width,
tx_width will save the transfer width, but for memcpy, either source or destination transfer width is taken as tx_width.

Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 9e1ad73..4c101a9 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -615,6 +615,7 @@
 	/* First descriptor of the chain embedds additional information */
 	first->txd.cookie = -EBUSY;
 	first->len = len;
+	first->tx_width = src_width;
 
 	/* set end-of-link to the last link descriptor of list*/
 	set_desc_eol(desc);
@@ -761,6 +762,7 @@
 	/* First descriptor of the chain embedds additional information */
 	first->txd.cookie = -EBUSY;
 	first->len = total_len;
+	first->tx_width = reg_width;
 
 	/* first link descriptor of list is responsible of flags */
 	first->txd.flags = flags; /* client is in control of this ack */
@@ -919,6 +921,7 @@
 	/* First descriptor of the chain embedds additional information */
 	first->txd.cookie = -EBUSY;
 	first->len = buf_len;
+	first->tx_width = reg_width;
 
 	return &first->txd;